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1. First online X‐ray fluorescence characterization of liquid‐liquid extraction in microfluidics

Author: Jean Duhamet, Thomas Zemb, Jean-Christophe P. Gabriel, Johannes Theisen, Asmae El Maangar, Varun Rai, Fabien Olivier, Ange Maurice, Nanyang Technological University [Singapour], Université Grenoble Alpes (UGA), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), Université de Montpellier (UM), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN UMR 3685), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences et technologies pour une Economie Circulaire des énergies bas carbone (ISEC), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Département de recherche sur les procédés pour la mine et le recyclage du combustible (DMRC), European Project: 320915,EC:FP7:ERC,ERC-2012-ADG_20120216,REE-CYCLE(2013), Nanyang Technological University (NTU), Nanyang Technological University, Energy Research Institute at NTU (ERIAN), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), CEA- Saclay (CEA), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Energy Research Institute @ NTU (ERI@N), and SCARCE Laboratory
Subjects: Materials science, liquid-liquid extraction, rare earth, Microfluidics, Rare earth, Kinetics, microfluidics, Analytical chemistry, X-ray fluorescence, 02 engineering and technology, 010402 general chemistry, online x‐ray fluorescence, 01 natural sciences, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Liquid–liquid extraction, online x-ray fluorescence, [CHIM]Chemical Sciences, anisotropic interface resistance, Materials of engineering and construction. Mechanics of materials, ComputingMilieux_MISCELLANEOUS, Chemical engineering [Engineering], Anisotropic Interface Resistance, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Characterization (materials science), kinetics, TA401-492, 0210 nano-technology, liquid‐liquid extraction
Abstract: Liquid-liquid extraction is a complex chemical purification process, which is associated with many thermodynamic and kinetic values. This makes its application in the recycling industry difficult, as it deals with waste streams that have highly variable compositions. In this regard, modelling an extraction process using microfluidics proves to be a useful approach to allow rapid adaptation to such composition changes, if development can be shown to be more accurate, faster, and safer than the classical batch approach with separate analysis. Here, the first automated microfluidic tool integrated with online X-ray fluorescence (XRF) is reported to study liquid-liquid extraction processes by enabling metal concentration quantification. The measurement is automated and performed for both aqueous and organic phases to improve accuracy. Overall, this fully automated approach shows that: (i) Thermodynamic and kinetic values associated with these processes can rapidly and efficiently be obtained simultaneously (in less than 13 hours with a resulting liquid use of less than 20 mL). (ii) Numerical simulations are consistent with the experimental data and provide rare insights regarding the respective contributions to the overall kinetic of the extraction system. Ministry of National Development (MND) Ministry of the Environment and Water Resources National Environmental Agency (NEA) National Research Foundation (NRF) Published version J.C.G., O.F., A.M., V.R. acknowledge financial support from SCARCE project, which is supported by the National Research Foundation, Prime Minister’s Office, Singapore, the Ministry of National Development, Singapore, and National Environment Agency, Ministry of the Environment and Water Resource, Singapore under the Closing the Waste Loop R&D Initiative as part of the Urban Solutions & Sustainability–Integration Fund (Award No.USS-IF-2018-4). J.D., J.C.G., A.E.M., J.T, T.Z acknowledge funding from the European Research Council under the European Union’s 7th Framework Program (FP/2007-2013)/ERC Grant Agreement N◦[320915] “REE-CYCLE”: Rare Earth Element reCYCling with Low harmful Emissions.
Published: 2021
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2. Influence of cerium salt concentration, co-solvents and water on the efficiency of supercritical CO2 extraction

Author: Sofyane Bouali, Antoine Leybros, Guillaume Toquer, Agnès Grandjean, and Thomas Zemb
Subjects: Materials science, Supercritical carbon dioxide, General Chemical Engineering, Extraction (chemistry), chemistry.chemical_element, Substrate (chemistry), 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Supercritical fluid, 0104 chemical sciences, Cerium nitrate, Cerium, chemistry.chemical_compound, chemistry, Nitrate, Chemical engineering, 0210 nano-technology, Ternary operation
Abstract: The extraction of cerium from cotton substrate, as a matrix model, using supercritical CO2 modified with phosphorus extractant and co-solvent/water in wise proportions, has been investigated. Using a recently developed isobutyl amidophosphonate extractant, the aim of this study was to emphasize how besides the usually considered operating parameters (flow rate, pressure and temperature), the efficiency of supercritical CO2 extraction of cerium depends on the concentration of cerium nitrate deposits on the substrate (between 0.27 and 261 mg gcotton−1) and on the presence and composition of co-solvent/water mixture as well. The variations of the extraction efficiency with the nature of the Ce nitrate deposits (aggregates or homogenous layers) are explained by using a deposition model confirmed using SEM and coupled with SAXS data. Extraction is promoted when Ce nitrates deposits are in the form of segregated aggregates instead of homogeneous layers. Phase equilibrium data for CO2-ethanol-amidophosphonate and CO2-isopropanol-amidophosphonate ternary systems have been measured at 40 °C and 25 MPa to investigate the benefit of using a co-solvent. Extraction experiments show that adding a co-solvent and carefully adjusting the water concentration up to 30%wt are crucial to obtain high mass extraction yields, here up to 82%.
Published: 2021
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3. Phase separation of binary mixtures induced by soft centrifugal fields

Author: Rose Rosenberg, Stjepan Marčelja, Thomas Zemb, Helmut Cölfen, Werner Kunz, Jean-François Dufrêche, Dominik Horinek, Dirk Haffke, Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), University of Konstanz, Australian National University (ANU), Modélisation Mésoscopique et Chimie Théorique (LMCT), University of Regensburg, European Project: 320915,EC:FP7:ERC,ERC-2012-ADG_20120216,REE-CYCLE(2013), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Phase transition, Molar mass, Materials science, Opacity, Spinodal decomposition, General Physics and Astronomy, Thermodynamics, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Colloid, Critical opalescence, Critical point (thermodynamics), Sedimentation equilibrium, ddc:540, Physical and Theoretical Chemistry, 0210 nano-technology
Abstract: International audience; We use the model system ethanol–dodecane to demonstrate that giant critical fluctuations induced by easily accessible weak centrifugal fields as low as 2000g can be observed above the miscibility gap of a binary liquid mixture. Moreover, several degrees above the phase transition, i.e. in the one-phase region, strong gradients of ethanol concentration occur upon centrifugation. In this case, the standard interpretation of sedimentation equilibrium in the analytical ultracentrifuge (AUC) yields an apparent molar mass of ethanol three orders of magnitude higher than the real value. Notably, these composition gradients have no influence on the distribution gradient of solutes such as dyes like Nile red. The thick opaque interphase formed upon centrifugation does not appear as the commonly observed sharp meniscus, but as a turbidity zone, similar to critical opalescence. This layer is a few millimeters thick and separates two fluids with low compositional gradients. All these effects can be qualitatively understood and explained using the Flory–Huggins solution model coupled to classical density functional theory (DFT). In this domain hetero-phase fluctuations can be triggered by gravity even far from the critical point. Taking into account Jean Perrin's approach to external fields in colloids, a self-consistent definition of the Flory effective volume and an explicit calculation of the total free energy per unit volume is possible.
Published: 2021
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4. Microemulsion as model to predict free energy of transfer of electrolyte in solvent extraction

Author: Jean-François Dufrêche, Thomas Zemb, Simon Gourdin-Bertin, Magali Duvail, Modélisation Mésoscopique et Chimie Théorique (LMCT), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), ANR-18-CE29-0010,MULTISEPAR,Modelisation multi-échelle des phases organiques pour l'extraction liquid-liquide(2018), European Project: 320915,EC:FP7:ERC,ERC-2012-ADG_20120216,REE-CYCLE(2013), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), Université de Montpellier (UM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), and Université de Montpellier (UM)
Subjects: General Chemical Engineering, Thermodynamics, 02 engineering and technology, Electrolyte, 010402 general chemistry, 01 natural sciences, symbols.namesake, thermodynamics, Phase (matter), Microemulsion, Aqueous solution, Chemistry, Extraction (chemistry), Langmuir adsorption model, General Chemistry, 021001 nanoscience & nanotechnology, solvent extraction, 0104 chemical sciences, Solvent, Condensed Matter::Soft Condensed Matter, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Volume fraction, symbols, 0210 nano-technology, mesoscopic modelling
Abstract: Special Issue on Hierarchical Organization in Solvent Extraction; International audience; We consider here the extraction of metals in the form of salts transferred from an aqueous to a solvent phase. Extraction is triggered by complexation and quenched by the associated necessary reorganization of the structured solvent phase. The extraction of ions changes the relative fraction of extractant molecules that is not part of the highly curved surfactant monolayer and is dispersed molecularly in the oil, and also the polar volume fraction including co-extracted water. The free energy and corresponding microstructures of the water-poor microemulsions are modelled in the frame of the Gaussian random fields (GRF) model. The curvature frustration energy significantly contributes to the free energy of extraction. A typical example of predicted isotherm using the GRF model is compared to the classically considered supramolecular complex formation, together with a minimal Langmuir model and an explicit monomer-to-film equilibrium of amphiphilic extractant. The corresponding small-angle scattering spectra and morphology changes are shown. One implication is that selectivity between a hydrated and a non-hydrated species is concentration dependent and cannot be considered as a constant as a function of the extractant concentration.
Published: 2022
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5. How acidity rules synergism and antagonism in liquid–liquid extraction by lipophilic extractants — Part II: application of the ienaic modelling

Author: Stéphane Pellet-Rostaing, Sandrine Dourdain, J. Rey, Klemen Bohinc, Mario Špadina, Jean-François Dufrêche, Thomas Zemb, Modélisation Mésoscopique et Chimie Théorique (LMCT), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), Université de Montpellier (UM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM), Université de Montpellier (UM), University of Ljubljana, Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), ANR-18-CE29-0010,MULTISEPAR,Modelisation multi-échelle des phases organiques pour l'extraction liquid-liquide(2018), ANR-10-LABX-0005,CheMISyst,CHEmistry of Molecular and Interfacial Systems(2010), European Project: 320915,EC:FP7:ERC,ERC-2012-ADG_20120216,REE-CYCLE(2013), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Faculty of Health Sciences, University of Ljubljana
Subjects: solvent extraction, colloidal model, extraction landscape, polydispersity, aggregtaion, Chemistry, General Chemical Engineering, Inorganic chemistry, droplet model, synergy, 02 engineering and technology, General Chemistry, 010403 inorganic & nuclear chemistry, 01 natural sciences, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, 020401 chemical engineering, Liquid–liquid extraction, ienaics, 0204 chemical engineering, Solvent extraction, Antagonism, polydispersity in aggregation
Abstract: International audience; In this article Part II, we consider the application of ienaic modeling for solvent extraction of rare earths in the case of the mixed DMDOHEMA/HDEHP extractant system. The system exhibits a synergistic extraction effect depending on the acid concentration and the extractant mole fraction, as demonstrated in the experimental article Part I. In this work, we directly compare experimental findings with theoretical predictions of the droplet model. The model considers the effective free energy of transfer as a combination of competing molecular forces, but contrary to previous micelle models that focus only on the dominant stoichiometry, it allows calculations of free energies of every possible spherical aggregate. The resulting image of the extraction process is that different behaviors can be obtained depending on the acidity and mole fraction of extractants, which are associated with different aggregation regimes in a complex free energy landscape of the system. Nevertheless, self-assembly is tuned by the extraction of all solutes, and not only the target metal cations.
Published: 2022
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6. Synergistic Solvent Extraction Is Driven by Entropy

Author: Thomas Zemb, Jean-François Dufrêche, Mario Špadina, Klemen Bohinc, Modélisation Mésoscopique et Chimie Théorique (LMCT), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Faculty of Health Sciences, University of Ljubljana, Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), European Project: 320915,EC:FP7:ERC,ERC-2012-ADG_20120216,REE-CYCLE(2013), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and University of Ljubljana
Subjects: Green chemistry, complexation, Dispersity, Configuration entropy, General Physics and Astronomy, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Ion, Colloid, Amphiphile, General Materials Science, Chemistry, extraction landscape, General Engineering, Aqueous two-phase system, self-assembly, nanoscale, 021001 nanoscience & nanotechnology, 0104 chemical sciences, mesoscopic modeling, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, self-assembly nanoscale mesoscopic modeling extraction complexation extraction landscape, Chemical physics, extraction, Self-assembly, 0210 nano-technology
Abstract: International audience; In solvent extraction, the self-assembly of amphiphilic molecules into an organized structure is the phenomenon responsible for the transfer of the metal ion from the aqueous phase to the organic solvent. Despite their significance for chemical engineering and separation science, the forces driving the solute transfer are not fully understood. Instead of assuming the simple complexation reaction with predefined stoichiometry, we model synergistic extraction systems by a colloidal approach that explicitly takes into account the self-assembly resulting from the amphiphilic nature of the extractants. Contrary to the current paradigm of simple stoichiometry behind liquid–liquid extraction, there is a severe polydispersity of aggregates completely different in compositions, but similar in the free energy. This variety of structures on the nanoscale is responsible for the synergistic transfer of ions to the organic phase. Synergy can be understood as a reciprocal effect of chelation: it enhances extraction because it increases the configurational entropy of an extracted ion. The global overview of the complex nature of a synergistic mixture shows different regimes in self-assembly, and thus in the extraction efficiency, which can be tuned with respect to the green chemistry aspect.
Published: 2019
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7. Using Microemulsions: Formulation Based on Knowledge of Their Mesostructure

Author: Miriam Simon, Yeshayahu Talmon, Magali Duvail, Paula Malo de Molina, Thomas Zemb, Michael Gradzielski, Stranski Laboratorium für Physikalische und Theoretische Chemie, Technische Universität Berlin (TU), Modélisation Mésoscopique et Chimie Théorique (LMCT), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Centro de Física de Materiales (CFM) (CSIC−UPV/EHU) - Materials Physics Center (MPC), Basque Foundation for Science (Ikerbasque), Technion - Israel Institute of Technology [Haifa], Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), German Research Foundation, Agence Nationale de la Recherche (France), Technical University of Berlin / Technische Universität Berlin (TU), University of the Basque Country/Euskal Herriko Unibertsitatea (UPV/EHU), and Ikerbasque - Basque Foundation for Science
Subjects: Flexibility (engineering), 010405 organic chemistry, Chemistry, Direct imaging, Nanotechnology, General Chemistry, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Surface-Active Agents, Solvents, Microemulsion, Emulsions, Experimental methods
Abstract: Microemulsions, as thermodynamically stable mixtures of oil, water, and surfactant, are known and have been studied for more than 70 years. However, even today there are still quite a number of unclear aspects, and more recent research work has modified and extended our picture. This review gives a short overview of how the understanding of microemulsions has developed, the current view on their properties and structural features, and in particular, how they are related to applications. We also discuss more recent developments regarding nonclassical microemulsions such as surfactant-free (ultraflexible) microemulsions or ones containing uncommon solvents or amphiphiles (like antagonistic salts). These new findings challenge to some extent our previous understanding of microemulsions, which therefore has to be extended to look at the different types of microemulsions in a unified way. In particular, the flexibility of the amphiphilic film is the key property to classify different microemulsion types and their properties in this review. Such a classification of microemulsions requires a thorough determination of their structural properties, and therefore, the experimental methods to determine microemulsion structure and dynamics are reviewed briefly, with a particular emphasis on recent developments in the field of direct imaging by means of electron microscopy. Based on this classification of microemulsions, we then discuss their applications, where the application demands have to be met by the properties of the microemulsion, which in turn are controlled by the flexibility of their amphiphilic interface. Another frequently important aspect for applications is the control of the rheological properties. Normally, microemulsions are low viscous and therefore enhancing viscosity has to be achieved by either having high concentrations (often not wished for) or additives, which do not significantly interfere with the microemulsion. Accordingly, this review gives a comprehensive account of the properties of microemulsions, including most recent developments and bringing them together from a united viewpoint, with an emphasis on how this affects the way of formulating microemulsions for a given application with desired properties., T.Z. thanks the German Science Foundation (DFG) for providing a Mercator professorship within the International Research Training Group (IRTG) 1524 (SSNI) at the Technische Universität Berlin, as well as the Agence Nationale de la Recherche (ANR) for the LABEX “Chemisyst” grant ANR 2011-01-05 that made the long-term collaboration possible.
Published: 2021
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8. Triple role of sodium salicylate in solubilization, extraction, and stabilization of curcumin from Curcuma longa

Author: Verena Huber, Thomas Zemb, Ruth M. Gschwind, Didier Touraud, Asmae El Maangar, Johannes Gramüller, Pierre Degot, Lea Rohr, Werner Kunz, Universität Regensburg (UR), Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Ethyl acetate, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, chemistry.chemical_compound, Materials Chemistry, [CHIM]Chemical Sciences, Physical and Theoretical Chemistry, Solubility, Spectroscopy, Sodium salicylate, ComputingMilieux_MISCELLANEOUS, Ternary numeral system, Chemistry, Hydrotrope, Extraction (chemistry), 021001 nanoscience & nanotechnology, Condensed Matter Physics, 6. Clean water, Atomic and Molecular Physics, and Optics, 0104 chemical sciences, Electronic, Optical and Magnetic Materials, Solvent, Partition coefficient, 0210 nano-technology, Nuclear chemistry
Abstract: Solubility, extraction and stabilization of curcumin extracted from Curcuma longa are still a challenge. Either the solubility power of the extracting solvent mixture is not at its optimum or non-sustainable solvents are used or the curcumin instability against oxidation is a problem. In order to tackle these problems, we consider here a promising alternative solvent medium, which is a ternary system composed of water/sodium salicylate (an anionic, preservative hydrotrope)/ethyl acetate. The effects of the structuring of the system are also studied. The position of the new critical point and the orientation of tie-lines in the liquid/liquid area were determined and further examined via interfacial tension and diffusion ordered spectroscopy (DOSY NMR) measurements. The critical point between the mono-phasic region and the liquid/liquid area is a classical one, around which no special nano-structuring is found, in contrast to some other ternary mixtures with hydrotropes. The system was investigated in terms of its curcumin solubility and its extraction power thereof. Good extraction yields (~90% of the Soxhlet reference) could be achieved in the area of best solubility. Surprisingly, the hydrophobic curcumin shows a significant solubility in systems that contain a significant amount of water in presence of sodium salicylate. These mixtures are far from the critical point but show significant structuring. The solubility is even higher than in pure ethyl acetate. At the point of highest solubility (water/sodium salicylate/ethyl acetate 7/13/80 w/w/w) 15.48 mg of curcuminoids per g Curcuma longa are successfully extracted. The partition coefficient in the lower liquid/liquid two-phasic region was determined for a subsequent purification of curcumin by precipitation. Surprisingly, curcumin accumulates at the “oil-water” interface in the more polar phase. Sodium salicylate could be removed from the precipitated curcumin by washing it with water (no trace of sodium salicylate has been detected with NMR after the washing process). The preservative effect of salicylate against the oxidative effect of light on curcumin was found to be significant. A better stabilization of curcumin was observed far away from the critical point and was most efficient in the region, where aggregates could be detected. So, extraction, solubilization, and chemical stabilization of a light sensitive substance could be performed using an anti-oxidative hydrotrope.
Published: 2021
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9. Molecular Forces in Liquid–Liquid Extraction

Author: Jean-François Dufrêche, Mario Špadina, Stjepan Marčelja, Thomas Zemb, Stéphane Pellet-Rostaing, Ruđer Bošković Institute (IRB), Faculty of Health Sciences, University of Ljubljana, Modélisation Mésoscopique et Chimie Théorique (LMCT), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Australian National University (ANU), ANR-18-CE29-0010,MULTISEPAR,Modelisation multi-échelle des phases organiques pour l'extraction liquid-liquide(2018), European Project: 320915,EC:FP7:ERC,ERC-2012-ADG_20120216,REE-CYCLE(2013), University of Ljubljana, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, Entropy, Liquid-Liquid Extraction, Supramolecular chemistry, Ionic bonding, Context (language use), 02 engineering and technology, Molecular Dynamics Simulation, 010402 general chemistry, 01 natural sciences, Ion, Phase (matter), Electrochemistry, General Materials Science, Spectroscopy, Surfaces and Interfaces, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, Condensed Matter::Soft Condensed Matter, Solvent, Solutions, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Solvation shell, Membrane, Chemical physics, Solvents, 0210 nano-technology
Abstract: International audience; The phase transfer of ions is driven by gradients of chemical potentials rather than concentrations alone (i.e., by both the molecular forces and entropy). Extraction is a combination of high-energy interactions that correspond to short-range forces in the first solvation shell such as ion pairing or complexation forces, with supramolecular and nanoscale organization. While the latter are similar to the long-range solvent-averaged interactions in the colloidal world, in solvent extraction they are associated with lower characteristic lengths of the nanometric domain. Modeling of such complex systems is especially complicated because the two domains are coupled, whereas the resulting free energy of extraction is around kBT to guarantee the reversibility of the practical process. Nevertheless, quantification is possible by considering a partitioning of space among the polar cores, interfacial film, and solvent. The resulting free energy of transfer can be rationalized by utilizing a combination of terms which represent strong complexation energies, counterbalanced by various entropic effects and the confinement of polar solutes in nanodomains dispersed in the diluent, together with interfacial extractant terms. We describe here this ienaics approach in the context of solvent extraction systems; it can also be applied to further complex ionic systems, such as membranes and biological interfaces.
Published: 2021
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10. Phase diagrams and microstructures of aqueous short alkyl chain polyethylene glycol ether carboxylate and carboxylic acid triblock surfactant solutions

Author: Werner Kunz, Thomas Zemb, Asmae El Maangar, David Kleber, Patrick Denk, Jyotsana Lal, Universität Regensburg (UR), Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Chemical Sciences and Engineering Division [Argonne], Argonne National Laboratory [Lemont] (ANL), Northern Illinois University, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Aqueous solution, Ethylene oxide, Ionic bonding, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Micelle, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Biomaterials, chemistry.chemical_compound, Colloid and Surface Chemistry, chemistry, Chemical engineering, Dynamic light scattering, Pulmonary surfactant, Phase (matter), Lyotropic, [CHIM]Chemical Sciences, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract: Hypothesis The surfactant C8EO8CH2COOH (Akypo LF2) and its salts have a small hydrophobic and a significantly longer hydrophilic part. As a consequence, there must be a significant steric constraint, once these surfactant molecules form micelles. In addition, the partially charged headgroups should bring some additional fine-tuning via electrostatic interactions to this “essentially non-ionic” surfactant. Experiments Phase diagrams of binary mixtures of water and C8EO8CH2COOH are established over large concentration and temperature ranges, also at different pHs and in the presence of sodium and calcium ions. Surface tensions and osmotic pressures are measured to understand the systems. To evaluate the microstructures, also Dynamic Light Scattering and Small-Angle X-ray Scattering are performed. Findings Apart from the formation of coacervates at very low surfactant concentrations, spherical micelles persist over the whole concentration and temperature range and do not change in size and shape. At very high surfactant concentrations, above 60% by weight, where the headgroups are no longer fully hydrated, the standard core-shell structure of micelles vanishes and highly stabilized aggregates of 8–26 octyl chains are suspended in interdigitated polyoxyethylene layers and form an “osmotic brush”. When the acid is partially transformed to a sodium salt, the repulsion between the micelles increases, whereas bridging between micelles prevails, when the counterions are calcium cations. Remarkably, the negative charges of the headgroups are randomly distributed in the hydrophilic ethylene oxide shell. Altogether, a phase diagram without lyotropic liquid crystalline phases and an extreme shift of the cloud-point in temperature and composition is found, similar to the phase diagram of C8EO8OH already known in literature. The phase properties can be explained by the curvature and packing constraints together with the Lindemann rule applied to short hydrocarbon chains.
Published: 2020
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11. Colloidal sol of UO2 nanoparticles supported by multi-lamellar vesicles of carboxylate based surfactant

Author: Zijie Lu, Thomas Zemb, J. Lautru, Diane Rébiscoul, Nanomatériaux pour l'Energie et le Recyclage (LNER), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Etude de la Matière en Mode Environnemental (L2ME), Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: chemistry.chemical_classification, Carboxylic acid, technology, industry, and agriculture, chemistry.chemical_element, Nanoparticle, Ether, 02 engineering and technology, Uranium, 010402 general chemistry, 021001 nanoscience & nanotechnology, complex mixtures, 01 natural sciences, 7. Clean energy, 0104 chemical sciences, chemistry.chemical_compound, Colloid, Colloid and Surface Chemistry, chemistry, Chemical engineering, Uranium oxide, [CHIM]Chemical Sciences, Carboxylate, 0210 nano-technology, Mesoporous material
Abstract: International audience; Producing compact monoliths of mesoporous uranium oxide that are free from surface active components and able to be wet by highly radioactive solutions is of great interest for future nuclear technologies. In this direction, metastable colloidal sols of UO2 using U(IV) as precursor and carboxylic surfactants (Polyoxyethylene(9) oleyl ether carboxylic acid C16/18:1E9COOH and Polyoxyethylene(10) lauryl ether carboxylic acid C12E10COOH) have been successfully prepared by indirect precipitation for 6 pH 8 with a molar ratio between uranium and surfactant U/S
Published: 2020
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12. How Adsorption of Pheromones on Aerosols Controls Their Transport

Author: Ludovic Jami, Jérôme Casas, Jean-François Dufrêche, Thomas Zemb, Modélisation Mésoscopique et Chimie Théorique (LMCT), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de recherche sur la biologie de l'insecte UMR7261 (IRBI), Université de Tours-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Université de Tours (UT)-Centre National de la Recherche Scientifique (CNRS)
Subjects: 010405 organic chemistry, Chemistry, General Chemical Engineering, Transport theory, General Chemistry, respiratory system, 010402 general chemistry, Photochemistry, 01 natural sciences, complex mixtures, 0104 chemical sciences, Hydrophobe, Atmosphere, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Adsorption, 13. Climate action, Sex pheromone, Molecule, Pheromone, Polar, QD1-999, Research Article
Abstract: We propose a general transport theory for pheromone molecules in an atmosphere containing aerosols. Many pheromones are hydrophobic molecules containing polar groups. They are low volatile and have some properties similar to those of hydrotropes. They therefore form a nonsoluble film at the water–air interface of aerosols. The fate of a small pheromone puff in air is computed through reaction-diffusion equations. Partitioning of pheromones between the gas and the aerosol surface over time is studied for various climate conditions (available aerosol surface) and adsorption affinities (energy of adsorption). We show that, for adsorption energy above 30 kBT per molecule, transport of pheromones on aerosols dominates over molecular transport typically 10 s after pheromone emission, even when few adsorbing aerosols are present. This new communication path for airborne chemicals leads to distinctive features including enhanced signal sensibility and increased persistence of pheromone concentration in the air due to slow diffusion of aerosols. Each aerosol droplet has the ability to adsorb thousands of pheromones to the surface, keeping a “history” of the atmospheric content between emission and reception. This new mechanism of pheromone transport leads to dramatic consequences on insect sensing revisiting the way we figure the capture of chemical signals., Transport of pheromones on aerosols is the main transport path, with different features than gas transport. Modeling shows this is valid in most circumstances if the free energy is sufficiently large.
Published: 2020
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13. Bending: from thin interfaces to molecular films in microemulsions

Author: Jean-François Dufrêche, Thomas Zemb, Modélisation Mésoscopique et Chimie Théorique (LMCT), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), ANR-18-CE29-0010,MULTISEPAR,Modelisation multi-échelle des phases organiques pour l'extraction liquid-liquide(2018), European Project: 320915,EC:FP7:ERC,ERC-2012-ADG_20120216,REE-CYCLE(2013), and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Materials science, Polymers and Plastics, Thermodynamics, Flexural rigidity, 02 engineering and technology, Surfaces and Interfaces, 010402 general chemistry, 021001 nanoscience & nanotechnology, Curvature, 01 natural sciences, Micelle, 0104 chemical sciences, Condensed Matter::Soft Condensed Matter, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Colloid and Surface Chemistry, Rigidity (electromagnetism), Molecular film, Molecule, Microemulsion, Physical and Theoretical Chemistry, Thin film, 0210 nano-technology
Abstract: International audience; Surfactant film rigidity is a ubiquitous general concept that is quantified in two different units. We show here how to convert the bending rigidity from reduced units of a virtual infinitely thin film (not made of molecules) into the chemical unit (kJ.mol-1) of a realistic film of monomolecular thickness. In most cases molecular lengths are not negligible versus curvature radius. Two bending constants for the elasticity of thin-shelled solids can be defined, as introduced by Gauss, whereas only one physical bending constant taking into account that the film cannot be teared has been introduced in the nineties by Hyde and Ninham. The explicit conversion depends on the topology and is different in the quasi-planar approximation, as well as the “direct” o/w or “reverse” w/o case of spherical or cylindrical micelles. We show some examples for classical and nonclassical micelles and microemulsions of different topologies in (H,N coordinates).
Published: 2020
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14. A formulator’s cut of the phase prism for optimizing selective metal extraction

Author: Sandrine Dourdain, Thomas Zemb, Werner Kunz, Tobias Lopian, Institute of Physical and Theoretical Chemistry, Universität Regensburg, Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Materials science, business.industry, Extraction (chemistry), Waste material, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Curvature, 01 natural sciences, Stripping (fiber), 0104 chemical sciences, Metal, Colloid and Surface Chemistry, Phase (matter), visual_art, visual_art.visual_art_medium, [CHIM]Chemical Sciences, Prism, 0210 nano-technology, Process engineering, business, ComputingMilieux_MISCELLANEOUS, Phase diagram
Abstract: Solvent-based liquid-liquid extraction and stripping is the key separation method at the basis of all hydrometallurgical processes, such as those used to retrieve strategic metals from ores or waste material. During formulation of an efficient extraction system, chemical engineers often encounter instabilities and the formation of undesired phases. In order to avoid the appearance of those in practice, we propose a simple and convenient approach of the phase diagram, based on mole ratio of cations as the variable that controls interfacial curvature. The proposed formulator’s cut through the Gibbs phase prism is more adapted than fish-cuts or similar ones in the case of extraction and stripping formulation optimized against variation in the feed composition.
Published: 2018
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15. Combined supramolecular and mesoscale modelling of liquid–liquid extraction of rare earth salts

Author: Anwesa Karmakar, Magali Duvail, Jean-François Dufrêche, Michael Bley, Thomas Zemb, Modélisation Mésoscopique et Chimie Théorique (LMCT), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), European Project: 320915,EC:FP7:ERC,ERC-2012-ADG_20120216,REE-CYCLE(2013), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM)
Subjects: Aqueous solution, Materials science, Thermodynamic equilibrium, Supramolecular chemistry, Thermodynamics, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Ion, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Solvent, Colloid and Surface Chemistry, Liquid–liquid extraction, Microemulsion, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS, Stoichiometry
Abstract: International audience; We develop a minimal model of weak aggregation in water in the case of neutral extractant in a Winsor II regime, i.e. dispersed microemulsions in thermodynamic equilibrium with concentrated brine. All the terms involved in the free energy associated with the transfer of ions from a concentrated aqueous to an organised organic phase have been estimated: supramolecular effects, bulk terms, extractant film bending and electric polarisation terms. This allows the rationalization of the paradoxical observation of apparent stoichiometry: “constant” associated with the phase transfer that varies with the nature of the solvent and the bending properties of the surfactant. The extractant film is characterized by its spontaneous packing parameter (of the order of 4) and its intrinsic rigidity of the order of 6.25 kJ mol$^{−1}$ (2.5 $k_BT$). This multi-scale study combining supramolecular chemistry and mesoscale modelling approach allows a large reduction of the number of parallel apparent equilibria currently used for dimensioning extraction devices. Prediction power versus variations of water activity and temperature is in reasonable agreement with observations made in typical pilot cascade
Published: 2018
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16. Self-Regulated Ion Permeation through Extraction Membranes

Author: Thomas Zemb, Helmuth Möhwald, Jean Duhamet, Maximilian Pleines, CEA Marcoule, Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Max Planck Institute of Colloids and Interfaces, Max-Planck-Gesellschaft, Univ Regensburg, Inst Phys & Theoret Chem, D-93040 Regensburg, Germany, Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Chemistry, Extraction (chemistry), Analytical chemistry, 02 engineering and technology, Surfaces and Interfaces, Permeation, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, 0104 chemical sciences, Ion, Membrane, Ion binding, Chemical engineering, Phase (matter), Electrochemistry, General Materials Science, 0210 nano-technology, Selectivity, [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft], Dissolution, ComputingMilieux_MISCELLANEOUS, Spectroscopy
Abstract: Separation of rare earth compounds from water into an organic phase in practical cases requires the use of specific ion binding ligands in high concentrations. These tend to form complex liquid crystalline phases preferentially at ion-rich locations inside a pertraction membrane. They form a blocking layer above an ion concentration threshold, which is experimentally characterized. It is shown to limit the flux through the membrane, which is studied for the application of rare earth recycling, an example being the phase transfer of Nd from water into organic phase. This feedback leads to a stationary membrane permeation rate that can be modeled without any free parameters in very good agreement with experiment. The ion-specific formation and dissolution of the blocking layer, a feature found also in nature, and its control suggest further studies to enhance permeation as well as its selectivity control.
Published: 2017
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17. Structured solvent effects on precipitation

Author: Thomas Zemb, Sophie Charton, Hans Riegler, Helmuth Möhwald, Marie Jehannin, and Bruno Corso
Subjects: Materials science, Polymers and Plastics, Precipitation (chemistry), Inorganic chemistry, Oxalic acid, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Oxalate, 0104 chemical sciences, Cerium nitrate, chemistry.chemical_compound, Colloid and Surface Chemistry, chemistry, Emulsion, Materials Chemistry, Particle, Physical and Theoretical Chemistry, Solvent effects, 0210 nano-technology, Cerium oxalate
Abstract: The synthesis of cerium oxalate, a reaction intermediate in the preparation of high performance ceramics, is studied in sessile droplets. We compare here the effect of alcoholic solvents with the usage of structured solvents, namely ultra-flexible microemulsions in the water-rich and oil-rich configurations. The nucleation and the growth of cerium oxalate particles are the result of local mixing by the Marangoni flow of droplets loaded with oxalic acid and cerium nitrate. The morphology of the particles is very different depending on the composition of the solvent and on the mixing process. We show that the variation of the particle morphology results from the difference of the structured solvent microphases during the precipitation process. When the precipitation occurs in a water continuous phase, usual needle-like oxalate particles precipitate. When the precipitate is formed in the dispersed phase of the emulsion, structured aggregates, as close-packed aggregates of needles, are compacted by microcapillarity effects.
Published: 2017
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18. A minimal predictive model for better formulations of solvent phases with low viscosity

Author: Jean Duhamet, Maximilian Pleines, Maximilian Hahn, Thomas Zemb, Univ Regensburg, Inst Phys & Theoret Chem, D-93040 Regensburg, Germany, Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), COSMOlogic GmbH & Co KG, Département de recherche sur les procédés pour la mine et le recyclage du combustible (DMRC), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Mesoscopic physics, Work (thermodynamics), Materials science, Thermodynamics, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, lcsh:TK9001-9401, 0104 chemical sciences, Minimal model, Viscosity, Macroscopic scale, Phase (matter), lcsh:Nuclear engineering. Atomic power, [CHIM]Chemical Sciences, Microemulsion, 0210 nano-technology, Nanoscopic scale
Abstract: The viscosity increase of the organic phase when liquid–liquid extraction processes are intensified causes difficulties for hydrometallurgical processes on industrial scale. In this work, we have analyzed this problem for the example of N,N-dialkylamides in the presence of uranyl nitrate experimentally. Furthermore, we present a minimal model at nanoscale that allows rationalizing the experimental phenomena by connecting the molecular, mesoscopic and macroscopic scale and that allows predicting qualitative trends in viscosity. This model opens broad possibilities in optimizing constraints and is a further step towards knowledge-based formulation of extracting microemulsions formed by microstructures with low connectivity, even at high load with heavy metals.
Published: 2020
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19. Amidophosphonate ligands as cerium extractants in supercritical CO$_2$

Author: Antoine Leybros, Guillaume Toquer, Antoine Leydier, Agnès Grandjean, Sofyane Bouali, Thomas Zemb, CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Nanomatériaux pour l'Energie et le Recyclage (LNER), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), This work was supported by funding from the CEA through the VADEN project, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: General Chemical Engineering, chemistry.chemical_element, 02 engineering and technology, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 010402 general chemistry, 01 natural sciences, Supercritical carbon dioxide, Molecule, Physical and Theoretical Chemistry, Solubility, Alkyl, chemistry.chemical_classification, Chemistry, solubility, Extraction (chemistry), 021001 nanoscience & nanotechnology, Condensed Matter Physics, extraction capacity, amidophosphonate, Supercritical fluid, 0104 chemical sciences, Cerium, cerium, Gravimetric analysis, Physical chemistry, 0210 nano-technology
Abstract: International audience; Industrial-scale rare earth extraction is typically performed by liquid-liquid extraction with large amounts of solvents, acids and organophosphorus ligands. An alternative is to use these extractants in supercritical CO$_2$ (SC-CO$_2$), where the crucial operating parameter is their solubility. Different molecules with amidophosphonate backbones have been synthesized and investigated in view of improving their solubility in SC-CO$_2$ and thereby their cerium extraction capacity. The CO$_2$-philicity of these extractants was adjusted by attaching branched or linear alkyl chains with four, six and eight carbons. Using a dynamic gravimetric setup, the solubility and cerium extraction capacity of these molecules were measured to vary from 1.56 to 2.47 mmol$_{ligand}$.mol$_{CO2}$$^{-1}$ and 0.25 to 0.46 mmol$_{Ce}$.mol$_{ligand}$$^{-1}$, respectively.The two properties were correlated and in both cases the highest values were obtained with a diisobutylamine chain. Solubility measurements between 313 and 331 K and between 13 and 28 MPa shows that optimal condition is (320 K ; 28 MPa).
Published: 2019
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20. Effects of porous media on extraction kinetics: Is the membrane really a limiting factor?

Author: J. Rey, Christophe Penisson, Johannes Theisen, Jean Duhamet, Thomas Zemb, Jean-Christophe P. Gabriel, Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Research Department on Mining and fuel Recycling Processes (LILA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN UMR 3685), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), SCARCE joint NTU/CEA laboratory (National Research Foundation, Prime Minister's Office, Singapore, the Ministry of National Development, Singapore, and National Environment Agency, Ministry of the Environment and Water Resource, Singapore under the Closing the Waste Loop R&D Initiative as part of the Urban Solutions & Sustainability – Integration Fund (Award No. USS-IF-2018-4)., European Project: 320915,EC:FP7:ERC,ERC-2012-ADG_20120216,REE-CYCLE(2013), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire Innovation en Chimie des Surfaces et NanoSciences (LICSEN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)
Subjects: Limiting factor, Work (thermodynamics), Materials science, lanthanide, Kinetics, Microfluidics, Thermodynamics, Filtration and Separation, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Biochemistry, Membrane technology, Reaction rate, Membrane extraction, diffusion coefficients, General Materials Science, Physical and Theoretical Chemistry, Extraction (chemistry), [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Membrane, 0210 nano-technology, Porous medium, Solvent-extraction, solvent- extraction
Abstract: International audience; Porous media in extraction and especially pertraction are often suspected to add unnecessary diffusive resistance and considerably slow down extraction kinetics. This work presents a miniaturized pertraction device and simulation of diffusive and reactive solute transport. Kinetics are experimentally observed and numerically fitted. Reaction rates – or solute transfer rates – are estimated via this fit on a numerical basis. The work shows that the diffusive resistance created by a porous medium is prevalent only at low distribution coefficients. At high distribution coefficients as is the case of quasi all industrial processes, the porous membrane does not interfere with overall kinetics. Instead, the diffusive resistance is shared between the feed and extraction phases, and the interface transfer, depending on the value of the transfer rate. Overall, this work can be generalize as enabling the measurement of solute transfer rates at the liquid-liquid interface, a key parameter in pertraction and membrane separation which is difficult to measure using classic methods of extraction.
Published: 2019
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21. Towards a general understanding of the effects of hydrophobic additives on the viscosity of surfactant solutions

Author: Thomas Zemb, Maximilian Pleines, Alina Scheklaukov, Daniel Benczédi, Werner Kunz, and Wolfgang Fieber
Subjects: Thermodynamics, 02 engineering and technology, Electrolyte, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, Micelle, Atomic and Molecular Physics, and Optics, Viscoelasticity, 0104 chemical sciences, Electronic, Optical and Magnetic Materials, chemistry.chemical_compound, Viscosity, chemistry, Pulmonary surfactant, Molecular film, Materials Chemistry, Microemulsion, Sodium laureth sulfate, Physical and Theoretical Chemistry, 0210 nano-technology, Spectroscopy
Abstract: Small amounts of nonpolar additives can have a tremendous impact on viscosity and viscoelasticity of giant micelles and completely change macroscopic properties. The effect can be best understood with the establishment of complete salt curves by screening surfactant viscosity as a function of electrolyte concentration. From previous studies in micellar systems of sodium laureth sulfate (SLES) with fragrance molecules, two independent mechanisms could be identified, co-solvent type interactions leading to a decrease of the maximum viscosity, and co-surfactant type interactions that cause the salt curve shift to the left. Our studies here reveal two new mechanisms with different effects on the salt curve. In particular, with long-chain hydrocarbons from n-octane to n-tetradecane a right shift was observed, whereas with short-chain or cyclic hydrocarbons such as n-hexane or cyclohexane the maximum viscosity increases. The two effects are interpreted via an extension of a recently developed thermodynamic model where changes in viscosity can be rationalized by a rebalance of the relative concentration of the three co-existing microphases: endcaps, cylinders and branching points. The right shift is linked to a continuous transformation of giant micelles into microemulsions containing an internal fluid. On the other hand, viscosity at maximum scales with the generalized bending constant of the molecular film forming the three microphases of the surfactant system. The total of four proposed mechanisms of solute-surfactant interactions that can impact amplitude and position of salt curves are independent and of different origin, but they are all intimately linked to the location of the additives within the surfactant film: headgroup, micellar interface, surfactant tail region or micellar core. Further investigation will be necessary to understand the molecular driving forces that position nonpolar additives within micellar aggregates, which would be the key for successful prediction of their impact on macroscopic viscosity.
Published: 2021
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22. Colloidal Model for the Prediction of the Extraction of Rare Earths Assisted by the Acidic Extractant

Author: Mario Špadina, Thomas Zemb, Jean-François Dufrêche, Klemen Bohinc, Modélisation Mésoscopique et Chimie Théorique (LMCT), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Faculty of Health Sciences, University of Ljubljana, Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), European Project: 320915,EC:FP7:ERC,ERC-2012-ADG_20120216,REE-CYCLE(2013), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and University of Ljubljana
Subjects: Colloidal model, solvent extraction, acidic extractants, self-assembly, Chemistry, Inorganic chemistry, Extraction (chemistry), 02 engineering and technology, Surfaces and Interfaces, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, 0104 chemical sciences, Condensed Matter::Soft Condensed Matter, Thermodynamic model, Metal, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Colloid, visual_art, Electrochemistry, visual_art.visual_art_medium, General Materials Science, Physics::Chemical Physics, 0210 nano-technology, Spectroscopy
Abstract: International audience; We propose the statistical thermodynamic model for the prediction of the liquid–liquid extraction efficiency in the case of rare-earth metal cations using the common bis(2-ethyl-hexyl)phosphoric acid (HDEHP) extractant. In this soft matter-based approach, the solutes are modeled as colloids. The leading terms in free-energy representation account for: the complexation, the formation of a highly curved extractant film, lateral interactions between the different extractant head groups in the film, configurational entropy of ions and water molecules, the dimerization, and the acidity of the HDEHP extractant. We provided a full framework for the multicomponent study of extraction systems. By taking into account these different contributions, we are able to establish the relation between the extraction and general complexation at any pH in the system. This further allowed us to rationalize the well-defined optimum in the extraction engineering design. Calculations show that there are multiple extraction regimes even in the case of lanthanide/acid system only. Each of these regimes is controlled by the formation of different species in the solvent phase, ranging from multiple metal cation-filled aggregates (at the low acid concentrations in the aqueous phase), to the pure acid-filled aggregates (at the high acid concentrations in the aqueous phase). These results are contrary to a long-standing opinion that liquid–liquid extraction can be modeled with only a few species. Therefore, a traditional multiple equilibria approach is abandoned in favor of polydisperse spherical aggregate formations, which are in dynamic equilibrium.
Published: 2019
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23. Molecular factors governing the viscosity peak of giant micelles in the presence of salt and fragrances

Author: Thomas Zemb, Wolfgang Fieber, Maximilian Pleines, Daniel Benczédi, and Werner Kunz
Subjects: chemistry.chemical_classification, Materials science, Aqueous solution, Salt (chemistry), Thermodynamics, 02 engineering and technology, Electrolyte, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Micelle, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Condensed Matter::Soft Condensed Matter, Biomaterials, chemistry.chemical_compound, Viscosity, Colloid and Surface Chemistry, Pulmonary surfactant, chemistry, Self-assembly, Sodium laureth sulfate, 0210 nano-technology
Abstract: Hypothesis The formation of transient networks of giant micelles leads to a viscosity peak when salt is added to aqueous solutions of charged surfactants. It is the consequence of an increase of the packing parameter due to charge screening of the surfactant headgroups, leading to a continuous transformation of the aggregates from spherical to wormlike micelles, and finally to branched networks. It should therefore be possible to predict the macroscopic viscosity of entangled giant micelles by modelling the packing parameter at nanoscale. Experiments A thermodynamic model is presented with a minimum of adjustable parameters, where branched networks are considered to be built from three coexisting microphases: cylinders, endcaps, and junctions. We use spontaneous packing parameters, in which the whole molecular length instead of the commonly used hydrocarbon chain length is considered. Standard reference chemical potentials and subsequently the occurrence of each microphase can be explicitly derived at specific electrolyte concentrations. Effective micellar length of giant micelles can be obtained from the microphase composition and is subsequently used to calculate the viscosity. Findings The model successfully predicts position and intensity of the viscosity maximum observed in experimental salt curves of sodium laureth sulfate (SLES). The robustness of the model was further investigated for various types of added salts or fragrance oils that affect differently spontaneous packing parameters or interfacial bending energy. An excellent agreement of the simulated salt curves with experimental data was achieved.
Published: 2018

24. Nanometric Surface Oscillation Spectroscopy of Water-Poor Microemulsions

Author: Mario Corti, Antonio Raudino, Laura Cantù, Maximilian Pleines, Thomas Zemb, Johannes Theisen, CNR Istituto per i Processi Chimico-Fisici (IPCF), Consiglio Nazionale delle Ricerche [Messina] (CNR), University of Catania [Italy], University of Milano, Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Univ Regensburg, Inst Phys & Theoret Chem, D-93040 Regensburg, Germany, Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Università degli Studi di Milano = University of Milan (UNIMI), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, Dodecane, 02 engineering and technology, Electrolyte, 010402 general chemistry, 01 natural sciences, Ion, Metal, chemistry.chemical_compound, Phase (matter), Electrochemistry, General Materials Science, Microemulsion, Spectroscopy, ComputingMilieux_MISCELLANEOUS, Surfaces and Interfaces, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, chemistry, Chemical engineering, Surface wave, visual_art, visual_art.visual_art_medium, 0210 nano-technology, [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft]
Abstract: Selectively exchanging metal complexes between emulsified water-poor microemulsions and concentrated solutions of mixed electrolytes is the core technology for strategic metal recycling. Nanostructuration triggered by solutes present in the organic phase is understood, but little is known about fluctuations of the microemulsion-water interface. We use here a modified version of an optoelectric device initially designed for air bubbles, in order to evidence resonant electrically induced surface waves of an oily droplet suspended in an aqueous phase. Resonant waves of nanometer amplitude of a millimeter-sized microemulsion droplet containing a common ion-specific extractant diluted by dodecane and suspended in a solution of rare earth nitrate are evidenced for the first time with low excitation fields (5 V/cm). From variation of the surface wave spectrum with rare earth concentration, we evidence uptake of rare-earth ions at the interface and at higher concentration the formation of a thin "crust" of liquid crystal forming at unusually low concentration, indicative of a surface induced phase transition. The effect of the liquid crystal structure on the resonance spectrum is backed up by a model, which is used to estimate crust thickness.
Published: 2018
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25. Influence of additives on the structure of surfactant-free microemulsions

Author: Sylvain Prévost, Thomas Zemb, Werner Kunz, Olivier Diat, Didier Touraud, Julien Marcus, Univ Regensburg, Inst Phys & Theoret Chem, D-93040 Regensburg, Germany, European Synchrotron Radiation Facility (ESRF), Ions aux Interfaces Actives (L2IA), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Ternary numeral system, Scattering, Chemistry, ddc:540, General Physics and Astronomy, 02 engineering and technology, Electrolyte, Neutron scattering, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Micelle, 0104 chemical sciences, Chemical engineering, Dynamic light scattering, 540 Chemie, Organic chemistry, Salting out, [CHIM]Chemical Sciences, Microemulsion, microemulsion stability electrolyte emulsification, Physical and Theoretical Chemistry, 0210 nano-technology
Abstract: We study the addition of electrolytes to surfactant-free microemulsions in the domain where polydisperse pre-Ouzo aggregates are present. As in previous studies, the microemulsion is the ternary system water/ethanol/1-octanol, where ethanol acts as co-solvent. Addition of electrolytes modifies the static X-ray and neutron scattering, and dynamic light scattering patterns, as well as the position of the miscibility gap, where spontaneous emulsification occurs upon dilution with water. All observations can be rationalized considering that electrolytes are either “salting out” the ethanol, which is the main component of the interface stabilizing the aggregates, or producing charge separation via the antagonistic ion effect discovered by Onuki et al. Amphiphilic electrolytes, such as sodium dodecylsulfate or sodium dietheylhexylphosphate, induce a gradual transition towards monodisperse ionic micelles with their characteristic broad scattering “peak”. In these micelles the ethanol plays then the role of a cosurfactant. Dynamic light scattering can only be understood by combination of fluctuations of aggregate concentration due to the vicinity of a critical point and in-out fluctuations of ethanol., Open Access Komponente aus der Allianzlizenz
Published: 2015
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26. Thermodynamic Description of Synergy in Solvent Extraction: II Thermodynamic Balance of Driving Forces Implied in Synergistic Extraction

Author: Michael Bley, Sandrine Dourdain, J. Rey, Stéphane Pellet-Rostaing, Simon Gourdin, Jean-François Dufrêche, Thomas Zemb, Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Modélisation Mésoscopique et Chimie Théorique (LMCT), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), ANR-10-LABX-0005,CheMISyst,CHEmistry of Molecular and Interfacial Systems(2010), European Project: 320915,EC:FP7:ERC,ERC-2012-ADG_20120216,REE-CYCLE(2013), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Stereochemistry, Thermodynamics, 02 engineering and technology, Electrolyte, 010402 general chemistry, 01 natural sciences, 7. Clean energy, Ion, Colloid, Phase (matter), Electrochemistry, Molecule, [CHIM]Chemical Sciences, General Materials Science, Spectroscopy, Dynamic equilibrium, Quantitative Biology::Biomolecules, Chemistry, Extraction (chemistry), Surfaces and Interfaces, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, Solvent, Condensed Matter::Soft Condensed Matter, 0210 nano-technology
Abstract: International audience; In the second part of this study, we analyze the free energy of transfer in the case of synergistic solvent extraction. This free energy of the transfer of an ion in dynamic equilibrium between two coexisting phases is decomposed into four driving forces combining long-range interactions with the classical complexation free energy associated with the nearest neighbors. We demonstrate how the organometallic complexation is counterbalanced by the cost in free energy related to structural change on the colloidal scale in the solvent phase. These molecular forces of synergistic extraction are driven not only by the entropic term associated with the tight packing of electrolytes in the solvent and by the free energy cost of coextracting water toward the hydrophilic core of the reverse aggregates present but also by the entropic costs in the formation of the reverse aggregate and by the interfacial bending energy of the extractant molecules packed around the extracted species. Considering the sum of the terms, we can rationalize the synergy observed, which cannot be explained by classical extraction modeling. We show an industrial synergistic mixture combining an amide and a phosphate complexing site, where the most efficient/selective mixture is observed for a minimal bending energy and maximal complexation energy.
Published: 2017
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27. Self-assembly, phase behaviour and structural behaviour as observed by scattering for classical and non-classical microemulsions

Author: Sylvain Prévost, Michael Gradzielski, Thomas Zemb, Institut Laue-Langevin (ILL), Technical University of Berlin / Technische Universität Berlin (TU), Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), ILL, Technische Universität Berlin (TU), and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Materials science, Scattering, Nanotechnology, 02 engineering and technology, Surfaces and Interfaces, Nonlinear Sciences::Cellular Automata and Lattice Gases, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Condensed Matter::Soft Condensed Matter, Reciprocal lattice, Colloid and Surface Chemistry, Chemical physics, Phase (matter), Monolayer, Cylinder, [CHIM]Chemical Sciences, Microemulsion, Physical and Theoretical Chemistry, Small-angle scattering, 0210 nano-technology, Scaling, ComputingMilieux_MISCELLANEOUS
Abstract: In this review, we discuss the conditions for forming microemulsions, systems which are thermodynamically stable mixtures of oil and water made stable by the presence of an interfacial film containing surface active molecules. There are several types of microemulsions, depending largely on the stiffness of the amphiphilic monolayer that separates the oily and the aqueous micro-domain. We first discuss and compare the phase behaviour of these different types, starting from the classical microemulsion made from a flexible surfactant film but then also moving on to less classical situations: this occurs when the interfacial film is stiff or when microemulsions are formed in the absence of a classical surfactant. In the second part, we relate these different microemulsion types to the structural features as can be determined via different methodologies by small angle scattering (SAS). Using absolute scaling, general theorems as well as fitting under constraints or to pre-supposed shapes in real space or correlation functions in reciprocal space allows to classify all microemulsions into classical flexible, rigid or ultra-flexible microemulsions with either globular, connected cylinder of locally flat interfaces, with the corresponding conductivity and phase stability properties.
Published: 2017
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28. The role of curvature effects in liquid–liquid extraction: assessing organic phase mesoscopic properties from MD simulations

Author: Magali Duvail, Jean-François Dufrêche, Thomas Zemb, Philippe Guilbaud, Yushu Chen, Steven van Damme, Modélisation Mésoscopique et Chimie Théorique (LMCT), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Département de recherche sur les procédés pour la mine et le recyclage du combustible (DMRC), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), European Project: 323282,EC:FP7:Fission,FP7-Fission-2012,SACSESS(2013), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Mesoscopic physics, Quantitative Biology::Biomolecules, Chemistry, Thermodynamics, Fluid mechanics, Flexural rigidity, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Curvature, 01 natural sciences, 0104 chemical sciences, Condensed Matter::Soft Condensed Matter, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Molecular dynamics, Computational chemistry, Molecular film, 0210 nano-technology, Order of magnitude, Complex fluid
Abstract: International audience; The bending rigidity of small reverse aggregates involved in liquid–liquid extraction processes has been investigated by molecular dynamics simulations. Simulations of a common extractant (DMDOHEMA) with four hydrophobic chains in explicit solvent (n-heptane) and in vacuum have been performed to determine the effect of solvent penetration on film stiffness. Elastic film bending energy that is needed for mesoscopic modelling of transfer of species between complex fluids is harmonic in terms of curvature (Helfrich formalism) and the packing parameter only if the solvent is explicitly taken into account. In terms of the packing parameter of the real molecular film constituting the reverse water in oil aggregates and taking into account molecular volume, area and film thickness (that is in agreement with Tanford's model), the bending rigidity is calculated to be about 16 kBT per extractant molecule (about 40 kJ mol−1), which is smaller than the free energy of transfer from an isolated “monomer” molecule to a weak aggregate, but of the order of magnitude of the free energy of transfer used in liquid–liquid extraction processes.
Published: 2017
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29. Thermodynamic description of synergy in solvent extraction: I. Enthalpy of mixing at the origin of synergistic aggregation

Author: Jean-François Dufrêche, Thomas Zemb, Stéphane Pellet-Rostaing, J. Rey, Julie M. Muller, Sandrine Dourdain, Laurence Berthon, Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Modélisation Mésoscopique et Chimie Théorique (LMCT), Département de recherche sur les procédés pour la mine et le recyclage du combustible (DMRC), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), ANR-10-LABX-0005,CheMISyst,CHEmistry of Molecular and Interfacial Systems(2010), European Project: 320915,EC:FP7:ERC,ERC-2012-ADG_20120216,REE-CYCLE(2013), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Chemistry, Extraction (chemistry), 02 engineering and technology, Surfaces and Interfaces, Flory–Huggins solution theory, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, Enthalpy of mixing, Thermodynamic equations, 01 natural sciences, Micelle, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Computational chemistry, Electrochemistry, Molecule, Organic chemistry, [CHIM]Chemical Sciences, General Materials Science, 0210 nano-technology, Solvent extraction, Spectroscopy
Abstract: International audience; Revisiting aggregation of extractant molecules into water-poor mixed reverse micelles, we propose in this paper to identify the thermodynamic origins of synergy in solvent extraction. Considering that synergistic extraction properties of a mixture of extractants is related to synergistic aggregation of this mixture, we identify here the elements at the origin of synergy by independently investigating the effect of water, acid, and extracted cations. Thermodynamic equations are proposed to describe synergistic aggregation in the peculiar case of synergistic solvent extraction by evaluating critical aggregation concentration (CAC) as well as specific interactions between extractants due to the presence of water, acid and cations. Distribution of two extractant molecules in the free extractants and in reverse micelles was assessed, leading to an estimation of the in-plane interaction parameter between extractants in the aggregates as introduced by Bergström and Eriksson (Bergström, M.; Eriksson, J. C. A Theoretical Analysis of Synergistic Effects in Mixed Surfactant Systems. Langmuir 2000, 16, 7173−7181). Based on this model, we study the N,N′-dimethyl-N,N′-dioctylhexylethoxymalonamide (DMDOHEMA) and di(2-ethylexyl) phosphoric acid (HDEHP) mixture and show that adding nitric acid enhances synergistic aggregation at the equimolar ratio of the two extractants and that this configuration can be related to a favored enthalpy of mixing.
Published: 2016
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30. A predictive model of reverse micelles solubilizing water for solvent extraction

Author: Bertrand Siboulet, Thomas Zemb, Jean-François Dufrêche, Michael Bley, Anwesa Karmakar, Modélisation Mésoscopique et Chimie Théorique (LMCT), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), European Project: 320915,EC:FP7:ERC,ERC-2012-ADG_20120216,REE-CYCLE(2013), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Solvent extraction, Thermodynamics, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Micelle, Biomaterials, symbols.namesake, Aggregation, Colloid and Surface Chemistry, Phase (matter), Solubility, Chromatography, Chemistry, Extraction (chemistry), Aqueous two-phase system, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Gibbs free energy, Condensed Matter::Soft Condensed Matter, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Bending energy, Critical micelle concentration, symbols, Chemical equilibrium, 0210 nano-technology
Abstract: International audience; Herein, a minimal model for the common case of W/O solubilization of badly soluble compounds present in an excess phase by reverse micellar aggregates in chemical equilibrium with its single compounds is introduced. A simple model of such liquid-liquid extractions is crucial for obtaining predictive parameter for the modelling of nuclear waste management and hydrometallurgic recycling strategies. The standard Gibbs free energy of aggregation and the concentration of the corresponding aggregate is calculated within a multiple-equilibria approach for a set of aggregate compositions of solute and amphiphilic extractant molecules. This minimal model provides potential surfaces estimating the stability of different aggregate compositions with 6.2 kJ mol−1 as a generalized bending constant. The complete concentrations of free and aggregated extractant species as well as the favored aggregation numbers, the polydispersity, the activity of the organic solvent, and the critical concentrations are captured by this thermodynamic model. An increase of the apparent critical micelle concentration for an increasing solute content in the aqueous phase is detected by this method.
Published: 2016
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31. How to explain microemulsions formed by solvent mixtures without conventional surfactants

Author: Tobias Lopian, Olivier Diat, Thomas Zemb, Dominik Horinek, Sylvain Prévost, Sebastian Schöettl, Julien Marcus, Didier Touraud, Stjepan Marčelja, Michael L. Klossek, Werner Kunz, Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Universität Regensburg (UR), Univ Regensburg, Inst Phys & Theoret Chem, D-93040 Regensburg, Germany, European Synchrotron Radiation Facility (ESRF), Ions aux Interfaces Actives (L2IA), and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: preouzo, micelles, Thermodynamics, 02 engineering and technology, Neutron scattering, 010402 general chemistry, 01 natural sciences, Micelle, Colloid, Organic chemistry, hydrotrope, Microemulsion, Multidisciplinary, Chemistry, Hydrotrope, aggregation, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Condensed Matter::Soft Condensed Matter, Solvent, Membrane, Physical Sciences, hydration force, 0210 nano-technology, Ternary operation, [PHYS.COND.CM-SCM]Physics [physics]/Condensed Matter [cond-mat]/Soft Condensed Matter [cond-mat.soft], surfactant-free microemulsions
Abstract: International audience; Ternary solutions containing one hydrotrope (such as ethanol) and two immiscible fluids, both being soluble in the hydrotrope at any proportion, show unexpected solubilization power and allow strange but yet unexplained membrane enzyme activity.We study the system-water-octanol as a simple model of such kinds of ternary solutions. The stability of “detergentless”micelles or microemulsions in such mixtures was proposed in the pioneering works of Barden and coworkers [Smith GD, Donelan CE, Barden RE (1977) J Colloid Interface Sci 60(3):488–496 and Keiser BA, Varie D, Barden RE, Holt SL (1979) J Phys Chem 83(10):1276–1281] in the 1970s and then, neglected, because no general explanation for the observations was available. Recent direct microstructural evidence by light, X-ray, and neutron scattering using contrast variation reopened the debate. We proposehere a general principle for solubilization without conventional surfactants: balance between hydration force and entropy. This balance explains the stability of microemulsions in homogeneous ternary mixtures based on cosolvents.
Published: 2016
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32. Editorial overview

Author: Thomas Zemb, Werner Kunz, Krister Holmberg, Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Universität Regensburg (UR), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Polymers and Plastics, Chemistry, Nanotechnology, 02 engineering and technology, Surfaces and Interfaces, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Colloid and Surface Chemistry, [CHIM]Chemical Sciences, Physical and Theoretical Chemistry, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2016
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33. Hydrotropes

Author: Werner Kunz, Krister Holmberg, Thomas Zemb, Universität Regensburg (UR), Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Colloid and Surface Chemistry, Polymers and Plastics, [CHIM]Chemical Sciences, 02 engineering and technology, Surfaces and Interfaces, Physical and Theoretical Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 0210 nano-technology, 01 natural sciences, ComputingMilieux_MISCELLANEOUS, 0104 chemical sciences
Abstract: International audience
Published: 2016
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34. Weak aggregation: State of the art, expectations and open questions

Author: Werner Kunz, Thomas Zemb, Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Universität Regensburg (UR), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Polymers and Plastics, Chemistry, Interface and colloid science, Nanotechnology, 02 engineering and technology, Surfaces and Interfaces, Inorganic electrolyte, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Organic molecules, Colloid and Surface Chemistry, [CHIM]Chemical Sciences, Physical and Theoretical Chemistry, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract: This paper gives an overview of weak aggregation due to long-range molecular forces beyond the first neighbor. Such subtle self-assemblies are an important part of modern colloidal chemistry and concern organic molecules as well as inorganic electrolytes and hybrid aggregates. Diverse aspects of such colloidal aggregations, as described in this special issue, can be characterized by the effective free energy per molecule involved. We discuss here expectations about emerging knowledge in this field and predictive modeling of inorganic as well as organic colloids and hybrid aggregates. Some still open questions are also given.
Published: 2016
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35. Liquid/liquid metal extraction: Phase diagram topology resulting from molecular interactions between extractant, ion, oil and water

Author: Jean-François Dufrêche, Thomas Zemb, Caroline Bauer, Pierre Bauduin, Olivier Diat, Ions aux Interfaces Actives (L2IA), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Modélisation Mésoscopique et Chimie Théorique (LMCT), Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, Dodecane, General Physics and Astronomy, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Micelle, Extractant Concentration, chemistry.chemical_compound, Colloid, Surfactant, [CHIM]Chemical Sciences, European Physical Journal Special Topic, General Materials Science, Microemulsion, Physical and Theoretical Chemistry, Topology (chemistry), Phase diagram, Extraction (chemistry), 021001 nanoscience & nanotechnology, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Condensed Matter::Soft Condensed Matter, chemistry, Chemical physics, Small-angle scattering, 0210 nano-technology, Reverse Micelle
Abstract: International audience; We consider the class of surfactants called “extractants” since they specifically interact with some cations and are used in liquid-liquid separation processes. We review here features of water-poor reverse micelles in water/oil/ extractant systems as determined by combined structural studies including small angle scattering techniques on absolute scale. Origins of instabilities, liquid-liquid separation as well as emulsification failure are detected. Phase diagrams contain the same multi-phase domains as classical microemulsions, but special unusual features appear due to the high spontaneous curvature directed towards the polar cores of aggregates as well as rigidity of the film made by extracting molecules.
Published: 2012
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36. Small-angle scattering and morphologies of ultra-flexible microemulsions

Author: Thomas Zemb, Sylvain Prévost, Olivier Diat, Tobias Lopian, Maximilian Pleines, European Synchrotron Radiation Facility (ESRF), Univ Regensburg, Inst Phys & Theoret Chem, D-93040 Regensburg, Germany, Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Ions aux Interfaces Actives (L2IA), and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: ultra-flexible microemulsions, Materials science, Small-angle X-ray scattering, Spinodal decomposition, Scattering, ternary phase diagrams, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, small-angle scattering (SAS), 01 natural sciences, General Biochemistry, Genetics and Molecular Biology, 0104 chemical sciences, Condensed Matter::Soft Condensed Matter, mesoscale solubilization, Crystallography, Critical point (thermodynamics), Chemical physics, [CHIM]Chemical Sciences, Microemulsion, Small-angle scattering, 0210 nano-technology, Ternary operation, surfactant-free microemulsions, Phase diagram
Abstract: The phase diagrams of ternary mixtures of partly miscible solvents containing a hydrotropic co-solvent exhibit a variable miscibility gap and one critical point. This work investigates the entire monophasic region far from and near to the miscibility gap in octan-1-ol/ethanol/water, for which ultra-flexible microemulsions (UFMEs) are observed by small-angle scattering techniques. SWAXS (combined small- and wide-angle X-ray scattering) allows the elucidation of these types of structure. Three distinct areas can be identified in the phase diagram, with scattering data resembling those from direct, bicontinuous and reverse local structures. These UFMEs are far more polydisperse than their surfactant-based counterparts. Water-rich and solvent-rich domains are only delimited by a small excess of hydrotrope, instead of a well defined surfactant layer of fixed area per molecule. It is shown that all scattering spectra obtained for the nanostructured compositions can be modelled by a simple unified analytical model composed of two uncorrelated contributions. The main one is the Ornstein-Zernike formula for composition fluctuations which gives information about the pseudo-phase domain size. The second is a Lorentzian that captures the structure of at least one of the coexisting pseudo-phases. No Porod law can be measured in the SAXS domain. The proposed expression gives access to two characteristic sizes as well as one inter-aggregate distance.The phase diagrams of ternary mixtures of partly miscible solvents containing a hydrotropic co-solvent exhibit a variable miscibility gap and one critical point. This work investigates the entire monophasic region far from and near to the miscibility gap in octan-1-ol/ethanol/water, for which ultra-flexible microemulsions (UFMEs) are observed by small-angle scattering techniques. SWAXS (combined small- and wide-angle X-ray scattering) allows the elucidation of these types of structure. Three distinct areas can be identified in the phase diagram, with scattering data resembling those from direct, bicontinuous and reverse local structures. These UFMEs are far more polydisperse than their surfactant-based counterparts. Water-rich and solvent-rich domains are only delimited by a small excess of hydrotrope, instead of a well defined surfactant layer of fixed area per molecule. It is shown that all scattering spectra obtained for the nanostructured compositions can be modelled by a simple unified analytical model composed of two uncorrelated contributions. The main one is the Ornstein-Zernike formula for composition fluctuations which gives information about the pseudo-phase domain size. The second is a Lorentzian that captures the structure of at least one of the coexisting pseudo-phases. No Porod law can be measured in the SAXS domain. The proposed expression gives access to two characteristic sizes as well as one inter-aggregate distance.
Published: 2016
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37. Morphologies Observed in Ultraflexible Microemulsions with and without the Presence of a Strong Acid

Author: Thomas Zemb, Dominik Horinek, Sebastian Schöttl, Sylvain Prévost, Tobias Lopian, Stéphane Pellet-Rostaing, Werner Kunz, Univ Regensburg, Inst Phys & Theoret Chem, D-93040 Regensburg, Germany, Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), European Synchrotron Radiation Facility (ESRF), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Phase boundary, General Chemical Engineering, Mesoscale meteorology, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, law.invention, lcsh:Chemistry, Molecular dynamics, law, [CHIM]Chemical Sciences, Microemulsion, Scattering, Chemistry, General Chemistry, 021001 nanoscience & nanotechnology, Synchrotron, 0104 chemical sciences, 3. Good health, Crystallography, lcsh:QD1-999, Macroscopic scale, Chemical physics, 0210 nano-technology, Ternary operation, Research Article
Abstract: We show that three different morphologies exist near the two-phase boundary of ternary systems containing a hydrotropic cosolvent. Based on synchrotron small- and wide-angle X-ray scattering combined with molecular dynamics, we rationalize the specific scattering signature of direct, bicontinuous, and reverse mesoscale solubilization. Surprisingly, these mesostructures are resilient toward strong acids, which are required in industrial applications. However, on a macroscopic scale, the phase boundary shifts in salting-in and salting-out in the direct and respectively reverse regime, leading to a crossing of the binodals., Ultraflexible microemulsions that contain a hydrotropic cosolvent exist in three morphologies. Stability is reinforced by concentrated sulfuric acid in the water-rich corner and weakened in the octanol-rich corner.
Published: 2016
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38. Membrane Densification of Heated Polyelectrolyte Multilayer Capsules Characterized by Soft X-ray Microscopy

Author: Christophe Déjugnat, Thomas Zemb, Helmuth Möhwald, Karen Köhler, Gleb B. Sukhorukov, Peter Guttmann, and Monique Dubois
Subjects: Materials science, Mechanical Engineering, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Polyelectrolyte, 0104 chemical sciences, Membrane, Chemical engineering, Mechanics of Materials, Polymer chemistry, Microscopy, Soft x-ray microscopy, General Materials Science, 0210 nano-technology
Published: 2007
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39. Catanionic surfactant systems—thermodynamic and structural conditions revisited

Author: Hacer Yalcinkaya, Vicknesh Kumar Gopalakrishnan, Thomas Zemb, Leonardo Chiappisi, Michael Gradzielski, Institut Laue-Langevin (ILL), Humboldt University Of Berlin, Institut fur Chemie, Technical University of Berlin / Technische Universität Berlin (TU), Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), ILL, Humboldt-Universität zu Berlin, Technische Universität Berlin (TU), and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: chemistry.chemical_classification, Polymers and Plastics, Chemistry, Bilayer, 02 engineering and technology, Neutron scattering, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Micelle, 0104 chemical sciences, Colloid and Surface Chemistry, Pulmonary surfactant, Chemical physics, Phase (matter), Amphiphile, Monolayer, Materials Chemistry, Organic chemistry, [CHIM]Chemical Sciences, Physical and Theoretical Chemistry, Counterion, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract: In this work, we review shortly the current state of knowledge about catanionic surfactant systems with a focus on the detailed understanding based on the molecular buildup of such systems and of the electrostatic interaction that controls their amphiphilic monolayer and bilayer. Particularly relevant here is the extent of hydrophobicity of the oppositely charged partners, which can range from just having a more or less hydrophobic counterion until a real surfactant of opposite charge. Based on this discussion, we then investigate different systems based on cetyltrimethylammonium (CTA) combined with either laurate (L) as an oppositely charged surfactant or naphthalenesulfonate (NS) as a strongly hydrophobic counterion. Both systems were studied for the case of having salt present by combining the two amphiphilic salts but also the salt-free situation which arises from combining the hydroxide with the acid. The phase behavior was determined as well as the mesoscopic structures present, as obtained by small-angle neutron scattering (SANS) and light scattering, which allow to discern formation of wormlike micelles and vesicles. Their presence was then further confirmed by rheological measurements, where in particular normal forces allow to distinguish the two types of aggregates, and control of rheology is a key property in such systems. In addition, the thermodynamic conditions in these systems were determined by means of differential scanning calorimetry (DSC). Based on these results, a consistent understanding of the formed structures and their macroscopic properties that arise from the molecular conditions in these systems is presented.
Published: 2015
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40. Self-assembly of myristic acid in the presence of choline hydroxide: Effect of molar ratio and temperature

Author: Audrey Arnould, Cédric Gaillard, Liliana G. Santiago, Anne-Laure Fameau, Thomas Zemb, Adrián A. Perez, Marc Anton, Jean-Paul Douliez, Fabrice Cousin, Unité de recherche sur les Biopolymères, Interactions Assemblages (BIA), Institut National de la Recherche Agronomique (INRA), Grupo Biocoloides y nanotecnologías (GBN), Universidad Nacional del Litoral [Santa Fe] (UNL), Biologie du fruit et pathologie (BFP), Université Bordeaux Segalen - Bordeaux 2-Institut National de la Recherche Agronomique (INRA)-Université Sciences et Technologies - Bordeaux 1, Laboratoire Léon Brillouin (LLB - UMR 12), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Saclay, Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université Bordeaux Segalen - Bordeaux 2-Institut National de la Recherche Agronomique (INRA)-Université Sciences et Technologies - Bordeaux 1 (UB), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Molar ratio, Inorganic chemistry, Lipid Bilayers, Myristic acid, molar ratio, 02 engineering and technology, INGENIERÍAS Y TECNOLOGÍAS, Conductivity, 010402 general chemistry, 01 natural sciences, Micelle, Myristic Acid, catanionic, Phase Transition, Choline, Biomaterials, chemistry.chemical_compound, Colloid and Surface Chemistry, Differential scanning calorimetry, Counter-ion, [CHIM]Chemical Sciences, counter-ion, chemistry.chemical_classification, Ions, Nanotecnología, Temperature, Fatty acid, Self-assembly, self-assembly, 021001 nanoscience & nanotechnology, Nano-materiales, Small-angle neutron scattering, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, chemistry, Hydroxide, fatty acid, Counterion, 0210 nano-technology, Catanionic
Abstract: Salt-free catanionic systems based on fatty acids and cationic surfactants are known to exhibit a broad polymorphism by simply tuning the molar ratio between the two components. In the case of fatty acid combined with organic amino counter-ions, very few data are available on the phase behavior obtained as a function of the molar ratio between the counter-ion and the fatty acid. In this study, we investigated the choline hydroxide/myristic acid system as a function of the molar ratio, R= n choline hydroxide/n myristic acid, and the temperature. At molecular scale, the ionization state of myristic acid was determined as a function of R by coupling pH, conductivity and infra-red spectroscopy measurements. At microscopic scale, the self-assemblies were characterized by small angle neutron scattering and microscopy experiments.For R1, all the myristic acid molecules were under their ionized form and only spherical micelles were present in solution. As in the case of catanionic systems, our study highlights that both R and temperature are two key parameters to finely control the self-assembly structure formed by myristic acid in the presence of choline hydroxide. Fil: Arnould, Audrey. Institut National de la Recherche Agronomique; Francia Fil: Perez, Adrián Alejandro. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Tecnología de los Alimentos; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Santa Fe; Argentina Fil: Gaillard, Cédric. Institut National de la Recherche Agronomique; Francia Fil: Douliez, Jean Paul. Institut National de la Recherche Agronomique; Francia Fil: Cousin, Fabrice. Centre National de la Recherche Scientifique; Francia Fil: Santiago, Liliana Gabriela. Universidad Nacional del Litoral. Facultad de Ingeniería Química. Instituto de Tecnología de los Alimentos; Argentina Fil: Zemb, Thomas. Centre National de la Recherche Scientifique; Francia Fil: Anton, Marc. Institut National de la Recherche Agronomique; Francia Fil: Fameau, Anne Laure. Institut National de la Recherche Agronomique; Francia
Published: 2015
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41. Calcium phosphate precipitation in catanionic templates

Author: Thomas Zemb, Benedicte Prelot, Laboratoire Interdisciplinaire sur l'Organisation Nanométrique et Supramoléculaire (LIONS), Nanosciences et Innovation pour les Matériaux, la Biomédecine et l'Energie (ex SIS2M) (NIMBE UMR 3685), Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Rayonnement Matière de Saclay (IRAMIS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Rayonnement Matière de Saclay (IRAMIS), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)
Subjects: Ammonium bromide, Materials science, Inorganic chemistry, Bioengineering, 02 engineering and technology, 010402 general chemistry, Mole fraction, 01 natural sciences, law.invention, Biomaterials, chemistry.chemical_compound, Pulmonary surfactant, law, Calcination, Surface charge, Precipitation (chemistry), Template, SAXS, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Phosphate, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Calcium phosphate, chemistry, Mechanics of Materials, Ionic strength, 0210 nano-technology, Catanionic
Abstract: International audience; A simple and effective mean for controlling electrostatic interactions during mineral precipitation in water is the use of a "catanionic" template. Such strategy is used to precipitate calcium phosphate (hydroxyapatite or HAP) and obtain mesoporous materials. Mixtures of catanionic surfactants with phosphate head-groups (polyoxyethylene oleyl ether phosphate) and a quaternary ammonium (myristyl trimethyl ammonium bromide) are used in order to obtain a template with adjustable surface charge and test the "charge-matching" effect. This effect manifests by a strong dependence of the template shape on molar fraction, which governs the charge per unit area of the surfactant as well as the growth of inorganic network. We first explore the effect of high ionic strength and pH variation on phase diagram of template. A hexagonal structure is observed for anionic surfactant, and such organization is still preserved in the presence of large quantity of cationic component. Synthesis of HAP is then performed using independently various volume fractions of template and various mole fraction of anionic component in the template. For samples with low amount of surfactant and an excess of anionic component, TOC analysis shows more than 80% of the added surfactant is trapped in the precipitate. These samples display in SAXS three peaks that are characteristic of a hexagonal structure. Such structure, where the repetition distance is much lower than twice surfactant chain length, has not yet been described in surfactant self-assembly. This must be a monolayer microstructure, but symmetry group is not known since higher orders cannot be detected. The HAP-template hybrid structure disappears after calcination, and the BET surface of calcined powders is smaller than for HAP particles synthesized in homogeneous conditions.
Published: 2005
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42. Weak Micelle-Like Aggregation in Ternary Liquid Mixtures as Revealed by Conductivity, Surface Tension and Light Scattering

Author: Vesna Sokol, Thomas Zemb, Perica Bošković, Didier Touraud, Werner Kunz, Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Universität Regensburg (UR), Univ Regensburg, Inst Phys & Theoret Chem, D-93040 Regensburg, Germany, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Octanol, Chemistry, Thermodynamics, 02 engineering and technology, Conductivity, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Micelle, Light scattering, 0104 chemical sciences, 3. Good health, Surfaces, Coatings and Films, Surface tension, chemistry.chemical_compound, microemulsions, conductivity, alcohols, surfactant-free, nanostructuring, pseudo-phases, Pulmonary surfactant, Materials Chemistry, Organic chemistry, [CHIM]Chemical Sciences, Microemulsion, Physical and Theoretical Chemistry, 0210 nano-technology, Ternary operation, ComputingMilieux_MISCELLANEOUS
Abstract: A very small concentration of NaBr is added to ternary, transparent, and thermodynamically stable mixtures of water, ethanol, and octanol. Measuring the electrical conductivity along lines with constant water to ethanol ratios reveals remarkable composition dependencies similar to those found in classical surfactant-based microemulsions. Indeed, light-scattering experiments along the same composition lines and additional surface tension measurements confirm the onset of aggregation and possibly direct, bicontinuous, and reversed structures in these surfactant-free systems such as in classical microemulsions.
Published: 2015
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43. The evaporation behavior of sessile droplets from aqueous saline solutions

Author: Thomas Zemb, Hans Riegler, Virginie Soulié, Philippe Prené, Helmuth Moehwald, Stefan Karpitschka, Florence Lequien, Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Max Planck Institute for Dynamics and Self-Organization (MPIDS), Max-Planck-Gesellschaft, Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), CEA Le Ripault (CEA Le Ripault), Direction des Applications Militaires (DAM), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Max Planck Institute of Colloids and Interfaces, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Université Paris-Sud - Paris 11 (UP11)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)
Subjects: chemistry.chemical_classification, Aqueous solution, Marangoni effect, [PHYS.NUCL]Physics [physics]/Nuclear Theory [nucl-th], Chemistry, Vapor pressure, aqueous, technology, industry, and agriculture, Analytical chemistry, Evaporation, General Physics and Astronomy, Salt (chemistry), Nanotechnology, 02 engineering and technology, [PHYS.NEXP]Physics [physics]/Nuclear Experiment [nucl-ex], 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Contact angle, Surface tension, Particle tracking velocimetry, Physical and Theoretical Chemistry, 0210 nano-technology
Abstract: International audience; Quantitative experiments on the evaporation from sessile droplets of aqueous saline (NaCl) solutions show a strong dependence on salt concentration and droplet shape. The experiments were performed with seven decades of initial NaCl concentrations, with various droplet sizes and with different contact angles. The evaporaton rate is significantly lower for high salt concentrations and small contact angles than what is expected from the well-accepted diffusion-controlled evaporation scenario for sessile drops, even if the change of the vapor pressure due to the salt is taken into account. Particle tracking velocimetry reveals that this modification of the evaporation behavior is caused by Marangoni flows that are induced by surface tension gradients originating from the local evaporative peripheral salt enrichment. In addition it is found that already very low salt concentrations lead to a pinning of the three phase contact line. Whereas drops with concentration ≥ 10-6M NaCl are pinned as soon as evaporation starts, drops with lower salt concentration do evaporate in a constant contact angle mode. Aside from new, fundamental insights the findings are also relevant for a better understanding of the widespread phenomenon of corrosion initiated by sessile drops.
Published: 2015
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44. Predicting for thermodynamic instabilities in water/oil/surfactant microemulsions: a mesoscopic modelling approach

Author: Jean-François Dufrêche, Magali Duvail, Thomas Zemb, Lise Arleth, Modélisation Mésoscopique et Chimie Théorique (LMCT), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Niels Bohr Institute [Copenhagen] (NBI), Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), ANR-12-BS08-0017,CELADYCT,Propriétés électriques de colloïdes par électroacoustique et conductivité dynamique : expériences et approches théoriques multiéchelles(2012), European Project: 320915,EC:FP7:ERC,ERC-2012-ADG_20120216,REE-CYCLE(2013), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and University of Copenhagen = Københavns Universitet (UCPH)-University of Copenhagen = Københavns Universitet (UCPH)
Subjects: Coalescence (physics), Scattering, Chemistry, General Physics and Astronomy, Thermodynamics, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, Curvature, 01 natural sciences, 0104 chemical sciences, Gaussian random field, Condensed Matter::Soft Condensed Matter, Physics::Fluid Dynamics, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Pulmonary surfactant, Oil droplet, Microemulsion, Physical and Theoretical Chemistry, 0210 nano-technology, Ternary operation
Abstract: International audience; The thermodynamics and structural properties of flexible and rigid nonionic water/oil/surfactant microemulsions have been investigated using a two level-cut Gaussian random field method based on the Helfrich formalism. Ternary stability diagrams and scattering spectra have been calculated for different surfactant rigidities and spontaneous curvatures. A more important contribution of the Gaussian elastic constants compared to the bending one is observed on the ternary stability diagrams. Furthermore, influence of the spontaneous curvature of the surfactant points out a displacement of the instability domains which corresponds to the difference between the spontaneous and effective curvatures. We enlighten that a continuous transition from a connected water in oil droplets to a frustrated locally lamellar (oil in water in oil droplets) microstructure is found to occur when increasing the temperature for an oil-rich microemulsion. This continuous transition translated in a shift in the scattering functions, points out that the phase inversion phenomenon occurs by a coalescence of the water droplets.
Published: 2014
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45. Reverse Aggregates as Adaptive Self-Assembled Systems for Selective Liquid-Liquid Cation Extraction

Author: Thomas Zemb, Jean-François Dufrêche, Magali Duvail, Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Modélisation Mésoscopique et Chimie Théorique (LMCT), and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Hydrometallurgy, Chemistry, Extraction (chemistry), aggregation, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Separation process, Solvent, interfaces, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Adsorption, metal extraction, Chemical engineering, Phase (matter), self‐assembly, Organic chemistry, Self-assembly, 0210 nano-technology, Complex fluid
Abstract: International audience; Separation of metals in the cationic form is the basis of hydrometallurgy. Ion‐specific separation is achieved via selective transfer between liquid phases that have been emulsified in order to be in “close” contact. We show here how the organization of water‐in‐oil (w/o) “reverse” aggregates in the solvent phase controls the free energy of transfer of cations in the form of neutral salts between phases. Indeed, all known efficient ion separation mechanisms rely on complex fluids in the Winsor II regime, i.e. when a concentrated mixed salt solution is in equilibrium with a solvent phase containing self‐assembled aggregates. Here, we point out that, in the general case of water‐poor complex fluids containing extractant molecules, long‐range interactions linked to w/o interface curvature participate in the selectivity of any multivalent ion extraction process. The free energy related to ion transfer between phases, i.e. the extraction free energy, is different from the complexation free energy. This difference is the key to the selectivity of the separation process. We give here general expressions linking complexation free energy and transfer free energy as derived from known adsorption isotherms, taking into account interfacial curvature, considered as a generalized scalar related to the packing near the interface.
Published: 2013
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46. How Do Anions Affect Self-Assembly and Solubility of Cetylpyridinium Surfactants in Water

Author: Thomas Zemb, Christophe Déjugnat, Jean-François Dufrêche, Olivier Diat, Wolfram Müller, Ions aux Interfaces Actives (L2IA), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Modélisation Mésoscopique et Chimie Théorique (LMCT), and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Hofmeister series, Chemistry, Inorganic chemistry, Cetylpyridinium, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Krafft temperature, Micelle, 0104 chemical sciences, Surfaces, Coatings and Films, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Chaotropic agent, chemistry.chemical_compound, Adsorption, Materials Chemistry, Pyridinium, Physical and Theoretical Chemistry, Solubility, 0210 nano-technology
Abstract: International audience; We report the specific effects of a series of anions (chloride, nitrate, and oxalate) on the solubility and self-assembly of cationic cetylpyridinium surfactants in water. The anion influence on micellization was evidenced by tensiometry and determination of Krafft temperatures. Anions strongly affect these parameters, depending on their position in the lyotropic series as well as on their “bridging” character. Scattering techniques (light, X-rays, and neutrons) were used to characterize the structures of micelles, and by solving a lateral equation of state approach, we show that chaotropic anions can be considered as adsorbed on the pyridinium head groups, inducing a decrease of the surface polarity and a Krafft temperature shift. Mixing different counteranions in various ratios led to a competition with a preferential adsorption at the micellar surface.
Published: 2013
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47. Impregnation and Swelling of Wood with Salts: Ion Specific Kinetics and Thermodynamics Effects

Author: Thomas Zemb, Aurelio Barbetta, Peter Fratzl, Luca Bertinetti, Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Max Planck Institute of Colloids and Interfaces, Max-Planck-Gesellschaft, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Salt (chemistry), 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Ion, Colloid, chemistry.chemical_compound, Adsorption, Interstitial matrix, Polymer chemistry, medicine, Cellulose, ComputingMilieux_MISCELLANEOUS, chemistry.chemical_classification, Mechanical Engineering, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Chaotropic agent, chemistry, Chemical engineering, 13. Climate action, Mechanics of Materials, Swelling, medicine.symptom, 0210 nano-technology
Abstract: The effects of salt impregnation are studied within wood cell walls, occurring upon soaking from concentrated salt solutions. Osmotic deswelling is in some cases followed by ion specific swelling linked to Hofmeister effects. Taking into account microstructure, this study models the free energy changes associated with the ions and water uptake at molecular, colloidal, and macroscopic mechanical scales, to show that slow swelling until osmotic equilibrium originates from charge separation of the salt diffused into wood cell wall material. Kinetic effects as well as mechanical effects linked to transfer of species and swelling of the interstitial matrix between cellulose crystals are discussed. Predictions by minimal models taking into account nonelectrostatic ion complexation allow to estimate the order of magnitude of the nonelectrostatic binding free energy of adsorbed chaotropic anions and complexed divalent cations to be 8 and 10 kJ mole–1, respectively.
Published: 2016
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48. Synergism by Coassembly at the Origin of Ion Selectivity in Liquid–Liquid Extraction

Author: Thomas Zemb, Sandrine Dourdain, Jacques Jestin, Jean-François Dufrêche, Antoine Leydier, O. Pecheur, Raphaël Turgis, I. Hofmeister, Stéphane Pellet-Rostaing, Fabienne Testard, Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Modélisation Mésoscopique et Chimie Théorique (LMCT), Laboratoire d'Ingénierie des Matériaux de Bretagne (LIMATB), Université de Bretagne Sud (UBS)-Université de Brest (UBO)-Institut Brestois du Numérique et des Mathématiques (IBNM), Université de Brest (UBO)-Université de Brest (UBO), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Université de Bretagne Sud (UBS)-Institut Brestois du Numérique et des Mathématiques (IBNM), and Université de Brest (UBO)-Université de Brest (UBO)-Université de Brest (UBO)
Subjects: Chemistry, Dodecane, Small-angle X-ray scattering, 02 engineering and technology, Surfaces and Interfaces, 010402 general chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 01 natural sciences, 0104 chemical sciences, Ion, Solvent, chemistry.chemical_compound, Chemical engineering, Liquid–liquid extraction, Phase (matter), Electrochemistry, Organic chemistry, [CHIM]Chemical Sciences, General Materials Science, 0210 nano-technology, Selectivity, Spectroscopy, ComputingMilieux_MISCELLANEOUS, Phase diagram
Abstract: In liquid-liquid extraction, synergism emerges when for a defined formulation of the solvent phase, there is an increase of distribution coefficients for some cations in a mixture. To characterize the synergistic mechanisms, we determine the free energy of mixed coassembly in aggregates. Aggregation in any point of a phase diagram can be followed not only structurally by SANS, SAXS, and SLS, but also thermodynamically by determining the concentration of monomers coexisting with reverse aggregates. Using the industrially used couple HDEHP/TOPO forming mixed reverse aggregates, and the representative couple U/Fe, we show that there is no peculiarity in the aggregates microstructure at the maximum of synergism. Nevertheless, the free energy of aggregation necessary to form mixed aggregates containing extracted ions in their polar core is comparable to the transfer free energy difference between target and nontarget ions, as deduced from the synergistic selectivity peak.
Published: 2012
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49. Crystalline Silicon under Acoustic Cavitation: From Mechanoluminescence to Amorphization

Author: Helmuth Möhwald, Ekaterina V. Skorb, Johann Ravaux, Matthieu Virot, Thomas Zemb, Rachel Pflieger, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Etude de la Matière en Mode Environnemental (L2ME), Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Max Planck Institute of Colloids and Interfaces, Max-Planck-Gesellschaft, and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, chemistry.chemical_element, 02 engineering and technology, Surface finish, 010402 general chemistry, 01 natural sciences, Physics::Fluid Dynamics, symbols.namesake, Crystalline silicon, Physical and Theoretical Chemistry, Composite material, ComputingMilieux_MISCELLANEOUS, Argon, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Crystallography, General Energy, chemistry, Excited state, Cavitation, symbols, Wetting, 0210 nano-technology, Raman spectroscopy, Mechanoluminescence
Abstract: The physicochemical behavior of crystalline silicon under acoustic cavitation is investigated in water sparged with argon at low temperature (10 and 20 °C). Surprisingly, spectroscopic investigations reveal that argon (bubbling continuously through the liquid phase during experiments) can be ultrasonically excited via mechanoluminescence, i.e., emission of light caused by mechanical action on a solid. This phenomenon is highlighted for the first time on an extended solid surface using these conditions and results from an interaction between the acoustically generated bubbles and the Si surface. The concomitant physical and chemical transformations induced at the solid–liquid interface are investigated (SEM, AFM) to characterize the generated stress and defects in combination with the roughness and wettability increases (evolving from ∼46° to ∼4°). Phase transformations of the Si lattice are observed (Raman spectroscopy, TEM) evidencing the complex stress state induced by acoustic cavitation in the Si crys...
Published: 2012
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50. Surfactin Self-Assembles into Direct and Reverse Aggregates in Equilibrium and Performs Selective Metal Cation Extraction

Author: Christophe Déjugnat, Olivier Diat, Thomas Zemb, Interactions moléculaires et réactivité chimique et photochimique (IMRCP), Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Fédération de Recherche Fluides, Energie, Réacteurs, Matériaux et Transferts (FERMAT), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD), and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Liquid-Liquid Extraction, 02 engineering and technology, 010402 general chemistry, Peptides, Cyclic, 01 natural sciences, Micelle, Metal, Lipopeptides, chemistry.chemical_compound, Liquid–liquid extraction, Cations, Phase (matter), Alkanes, Organic chemistry, [CHIM]Chemical Sciences, Physical and Theoretical Chemistry, Micelles, ComputingMilieux_MISCELLANEOUS, Extraction (chemistry), Aqueous two-phase system, Water, Hydrogen-Ion Concentration, 021001 nanoscience & nanotechnology, Atomic and Molecular Physics, and Optics, 0104 chemical sciences, chemistry, Chemical engineering, Metals, visual_art, visual_art.visual_art_medium, Self-assembly, 0210 nano-technology, Surfactin, Bacillus subtilis
Abstract: On tie-lines between water-rich and alkane-rich solutions, it is shown via scattering experiments that natural lipopeptide surfactin self-assembles into direct and reverse micelles in equilibrium. Elongated direct micelles in the aqueous phase are present together with small reverse globular aggregates in the organic phase. These latter are made from hydrated surfactant without any "water pool" in the organic phase. The resulting biphasic system is used for liquid-liquid extraction of model metal cations. It is efficient with iron but not with copper or neodymium. Competitive extractions show high selectivity towards iron.
Published: 2011
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