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103 results on '"Sadtler, Véronique"'

10. Is there a difference between surfactant-stabilised and Pickering emulsions?

Author

Dekker, Riande I., Velandia, Santiago F., Kibbelaar, Heleen V.M., Morcy, Azeza, Sadtler, Véronique, Roques-Carmes, Thibault, Groenewold, Jan, Kegel, Willem K., Velikov, Krassimir P., Bonn, Daniel, Dekker, Riande I., Velandia, Santiago F., Kibbelaar, Heleen V.M., Morcy, Azeza, Sadtler, Véronique, Roques-Carmes, Thibault, Groenewold, Jan, Kegel, Willem K., Velikov, Krassimir P., and Bonn, Daniel

Abstract

What measurable physical properties allow one to distinguish surfactant-stabilised from Pickering emulsions? Whereas surfactants influence oil/water interfaces by lowering the oil/water interfacial tension, particles are assumed to have little effect on the interfacial tension. Here we perform interfacial tension (IFT) measurements on three different systems: (1) soybean oil and water with ethyl cellulose nanoparticles (ECNPs), (2) silicone oil and water with the globular protein bovine serum albumin (BSA), and (3) sodium dodecyl sulfate (SDS) solutions and air. The first two systems contain particles, while the third system contains surfactant molecules. We observe a significant decrease in interfacial tension with increasing particle/molecule concentration in all three systems. We analyse the surface tension data using the Gibbs adsorption isotherm and the Langmuir equation of state for the surface, resulting in surprisingly high adsorption densities for the particle-based systems. These seem to behave very much like the surfactant system: the decrease in tension is due to the presence of many particles at the interface, each with an adsorption energy of a few kBT. Dynamic interfacial tension measurements show that the systems are in equilibrium, and that the characteristic time scale for adsorption is much longer for particle-based systems than for surfactants, in line with their size difference. In addition, the particle-based emulsion is shown to be less stable against coalescence than the surfactant-stabilised emulsion. This leaves us with the conclusion that we are not able to make a clear distinction between the surfactant-stabilised and Pickering emulsions.

Published
2023

11. Is there a difference between surfactant-stabilised and Pickering emulsions?

Author

Physical and Colloid Chemistry, Sub Physical and Colloid Chemistry, Dekker, Riande I., Velandia, Santiago F., Kibbelaar, Heleen V.M., Morcy, Azeza, Sadtler, Véronique, Roques-Carmes, Thibault, Groenewold, Jan, Kegel, Willem K., Velikov, Krassimir P., Bonn, Daniel, Physical and Colloid Chemistry, Sub Physical and Colloid Chemistry, Dekker, Riande I., Velandia, Santiago F., Kibbelaar, Heleen V.M., Morcy, Azeza, Sadtler, Véronique, Roques-Carmes, Thibault, Groenewold, Jan, Kegel, Willem K., Velikov, Krassimir P., and Bonn, Daniel

Published
2023

12. Probing interfaces of pea protein-stabilized emulsions with a fluorescent molecular rotor

Author

Velandia, Santiago F., Bittermann, Marius R., Mirzahossein, Elham, Giubertoni, Giulia, Caporaletti, Federico, Sadtler, Véronique, Marchal, Philippe, Roques-Carmes, Thibault, Meinders, M.B.J., Bonn, Daniel, Velandia, Santiago F., Bittermann, Marius R., Mirzahossein, Elham, Giubertoni, Giulia, Caporaletti, Federico, Sadtler, Véronique, Marchal, Philippe, Roques-Carmes, Thibault, Meinders, M.B.J., and Bonn, Daniel

Abstract

Pea protein isolate (Pisum sativum L., PPI) has been much studied in the last decade because of its potential as a bio-based alternative for surfactants to produce innovative and environmentally friendly emulsion products. PPI is ideal due to its favorable nutritional properties, low allergenicity and low environmental impact. Despite its growing popularity, understanding the stabilisation mechanism of emulsions stabilized with PPI remains a key question that requires further investigation. Here, we use fluorescence lifetime microscopy with molecular rotors as local probes for interfacial viscosity of PPI stabilized emulsions. The fluorescence lifetime correlates to the local viscosity at the oil-water interface allowing us to probe the proteins at the interfacial region. We find that the measured interfacial viscosity is strongly pH-dependent, an observation that can be directly related to PPI aggregation and PPI reconformation. By means of molecular rotor measurements we can link the local viscosity of the PPI particles at the interface to the Pickering-like stabilisation mechanism. Finally, this can be compared to the local viscosity of PPI solutions at different pH conditions, showing the importance of the PPI treatment prior to emulsification.

Published
2023

17. Screening of process parameters for the formulation of alginate microparticles with efficient encapsulation of fragile molecules using a Plackett-Burman design

Author

Mackin-Mohamour, Synthia, Bastogne, Thierry, Hassler, Lucie, Budzinski, Julia, Roques-Carmes, Thierry, Sadtler, Véronique, Lebrun, Maud, Marchal, Philippe, Sapin-Minet, Anne, Parent, Marianne, Cibles thérapeutiques, formulation et expertise pré-clinique du médicament (CITHEFOR), Université de Lorraine (UL), Centre de Recherche en Automatique de Nancy (CRAN), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Biology, genetics and statistics (BIGS), Inria Nancy - Grand Est, Institut National de Recherche en Informatique et en Automatique (Inria)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institut Élie Cartan de Lorraine (IECL), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), CYBERnano [Villers-lès-Nancy], and Laboratoire Réactions et Génie des Procédés (LRGP)

Subjects
[STAT.AP]Statistics [stat]/Applications [stat.AP], [SDV.CAN]Life Sciences [q-bio]/Cancer, [SPI.NANO]Engineering Sciences [physics]/Micro and nanotechnologies/Microelectronics, [SPI.SIGNAL]Engineering Sciences [physics]/Signal and Image processing
Abstract

Présentation Poster; National audience; Peptide drugs efficacy and safety are often limited by instability, short half-life, immunogenicity and their hydrophilic nature which compromises their transport across biological membranes. These limitations could be addressed by polymeric formulations produced with processes adapted to these hydrophilic and labile drugs. For example, S-nitrosoglutathione (GSNO) is a tripeptide, highly hydrophilic, and physiological form of storage of nitric oxide (NO). NO is involved in several physiological processes, particularly in the cardiovascular system. It inhibits platelet aggregation, prevents endothelial dysfunction and promotes vasodilation but NO bioavailability is decreased both by ageing and various diseases. GSNO has been shown to be safe in clinical trials and effective in various preclinical models. However, GSNO needs to be presented in an adapted galenicform for using as a prodrug for oral administration. Consequently, we have developed several polymeric particles based on alginate obtained by emulsion/gelation process that target the following specifications: efficient encapsulation of hydrophilic molecules, with a particle size control, release control. An optimization of the formulation is currently proposed. A model compound (FCF sun yellow) with similar physicochemical properties to GSNO is used during particle development, to facilitate the analytical steps. A 4-factor Plackett-Burman experimental design was carried out to optimize the formulation process using the Quality by Design development paradigm, including one critical material attribute and three process parameters. The physico-chemical characterization of particles was performed to identify the optimized process and formulation parameters.

Published
2021

19. Insight into the Emulsification Process Effect on Particles Distribution in Pickering Emulsions: a Series of Rheological and Gravimetric Tests

Author

Ramos, Diego, Sadtler, Véronique, Marchal, Phillipe, Lemaître, Cécile, Benyahia, Lazhar, Roques-Carmes, Thibault, Laboratoire Réactions et Génie des Procédés (LRGP), Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL), Institut des Molécules et Matériaux du Mans (IMMM), and Le Mans Université (UM)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
TK7885-7895, Computer engineering. Computer hardware, Chemical engineering, [CHIM]Chemical Sciences, TP155-156
Abstract

International audience; This work aims to develop a method to quantify the particles distribution in Pickering emulsions. Particle stabilized oil-in-water emulsions of different formulations were produced with different emulsification processes. These emulsions were then centrifugated to separate the oily from the aqueous phase. Successive rheological and gravimetric tests on the same aqueous phases provide information about the silica fraction adsorbed at the emulsion's interfaces and the particle interfacial concentration. The emulsification process changes the average droplet size of the emulsion, and results also show that the silica fraction in the dispersed phase and the silica interfacial concentration are modified. Moreover, the silica behaviour may be dictated by the nature of the stirrer, the time and the shear speed of the emulsification process.

Published
2021

21. Insight into the Emulsification Process Effect on Particles Distribution in Pickering Emulsions: a Series of Rheological and Gravimetric Tests.

Author

Ramos, Diego M., Sadtler, Véronique, Marchal, Phillipe, Lemaître, Cécile, Benyahia, Lazhar, and Roques-Carmes, Thibault

Subjects
GRAVIMETRY, RHEOLOGY, EMULSIONS, AQUEOUS solutions, THERMODYNAMICS, CHEMICAL processes
Abstract

This work aims to develop a method to quantify the particles distribution in Pickering emulsions. Particle stabilized oil-in-water emulsions of different formulations were produced with different emulsification processes. These emulsions were then centrifugated to separate the oily from the aqueous phase. Successive rheological and gravimetric tests on the same aqueous phases provide information about the silica fraction adsorbed at the emulsion's interfaces and the particle interfacial concentration. The emulsification process changes the average droplet size of the emulsion, and results also show that the silica fraction in the dispersed phase and the silica interfacial concentration are modified. Moreover, the silica behaviour may be dictated by the nature of the stirrer, the time and the shear speed of the emulsification process. [ABSTRACT FROM AUTHOR]

Published
2021
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22. Effect of Silica Nanoparticles in Xanthan Gum Solutions: Rheological Behavior and Preparation Methods of Nanofluids.

Author

Buitrago Rincon, Dayan L., Sadtler, Véronique, Mercado O., Ronald A., Roques-Carmes, Thibault, Marchal, Philippe, Pedraza A., Julio A., and Lemaitre, Cécile

Subjects
XANTHAN gum, SILICA nanoparticles, NANOFLUIDS, RHEOLOGY, LIGHT scattering
Abstract

In this article, different methods are investigated for the preparation of nanofluids composed of hydrocolloid xanthan gum (XG) and hydrophilic silica nanoparticles (NP) dispersed in water. The rheological behavior of the XG solutions and NP suspensions was first characterized individually, for different concentrations. The effect of the presence of salt (NaCl) was then evaluated. The polymer dilution curves were established, delimiting the dilute and semi-dilute regimes. Different preparation methods of the nanofluids were then considered, testing different factors like the hydration time of the polymer, the sonication time, and the order of aggregation of the components (XG - NP). Characterization techniques such as dynamic light scattering (DLS) and rheological characterization at constant temperature and variable shear rate were used, providing a trend in the stability of the viscous profile of nanofluids. The simplest method providing a correct dispersion of the NP as well as the increase of the viscous profile was then selected. Finally, the evolution in time of the nanofluids was studied and it was observed that the presence of NP stabilized the polymer solution by maintaining its viscosity level in time. This study provides a better understanding of the interactions between XG and silica NP in solution, through the rheological behavior of fluids at low concentrations. [ABSTRACT FROM AUTHOR]

Published
2021
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26. Dextranes modifiés pour la stabilisation d’emulsions huile dans l’eau très concentrées

Author

Lopez Gonzalez, E, Aguilera-Miguel, A, Sadtler, Véronique, Marchal, Philippe, Durand, Alain, Choplin, Lionel, UL, LCPM, Laboratoire Réactions et Génie des Procédés (LRGP), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie Physique Macromoléculaire (LCPM), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), and École Doctorale RP2E

Subjects
[CHIM.POLY] Chemical Sciences/Polymers, [CHIM.POLY]Chemical Sciences/Polymers, [CHIM.ORGA]Chemical Sciences/Organic chemistry, [CHIM.ORGA] Chemical Sciences/Organic chemistry, ComputingMilieux_MISCELLANEOUS
Abstract

National audience

Published
2015

27. Title: Making Use of the Formulation-Composition Map To Prepare Highly Concentrated Emulsions with Particular Rheological Properties

Author

Paruta-Tuarez, Emilio, Sadtler, Véronique, Marchal, Philippe, Choplin, Lionel, Salager, Jean-Louis, Laboratoire Réactions et Génie des Procédés (LRGP), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Laboratorio de Formulación, Interfases, Reología y Procesos (FIRP), Universidad de los Andes [Bogota] (UNIANDES), and Venezuelan Ministry of Science and Technology FONACIT-Venezuela MRES-France

Subjects
GEL-EMULSIONS, VOLUME FRACTION, AFFINITY INVERSION, VISCOELASTIC PROPERTIES, DROP SIZE, OIL-WATER-SYSTEMS, STABILITY, DYNAMIC INVERSION HYSTERESIS, [SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, PHASE-RATIO EMULSIONS, SURFACTANT
Abstract

International audience; The effects of the formulation and dispersed-phase weight fraction on rheological properties of highly concentrated water-in-oil emulsions are reported. Because the surfactant concentratiOn is kept constant, emulsion characteristics may be represented on a formulation composition bidimensional map. The formulation variable is the hydrophilic lipophilic balance (BIB) number of the nonionic surfactant or surfactant mixture which ranges from 4.3 to 10. Highly concentrated water-in-dodecane emulsions are prepared using a semibatch process, with a dispersed-phase weight fraction ranging from 0.90 to 0.98. Two major effects are observed in relation to the formulation influence: First, elastic modulus (G') remarkably decreases in the vicinity of optimum formulation whenever the affinity of the surfactant for the oil and water phases is exactly balanced (HLB = 10.5). Second, the elastic modulus value passes through a maximum, concomitant to a minimum drop size, at some distance of the so-called optimum formulation (HLB = 7.7). Hence, the use of a bidimensional formulation composition map allows one to control and to modulate the final rheological properties of highly concentrated emulsions.

Published
2011

28. Computational Fluid Dynamics: A tool to the formulation of therapeutic aerosols

Author

Bardin-Monnier, Nathalie, Marchal-Heussler, Laurent, Tita, Amal, Campos, Diana, Sadtler, Véronique, Marchal, Philippe, Falk, Véronique, Laboratoire Réactions et Génie des Procédés (LRGP), Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Université Henri Poincaré - Nancy 1 (UHP), and Université Paul Verlaine - Metz (UPVM)

Subjects
[SPI.GPROC]Engineering Sciences [physics]/Chemical and Process Engineering, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2008

29. Polylactide-grafted dextrans : synthesis and properties at interfaces and in solution

Author

Six, J.L., Nouvel, Cécile, Frochot, Céline, Sadtler, Véronique, DUBOIS, Philippe, Dellacherie, Edith, SIX, Jean-Luc, Laboratoire de Chimie Physique Macromoléculaire (LCPM), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), Département de Chimie Physique des Réactions (DCPR), Institut National Polytechnique de Lorraine (INPL)-Centre National de la Recherche Scientifique (CNRS), Centre de Génie Chimique des Milieux Rhéologiquement Complexes (GEMICO), Institut National Polytechnique de Lorraine (INPL), Laboratoire de Chimie des Matériaux et Polymères (SMPC), Université de Mons-Hainaut, Centre National de la Recherche Scientifique (CNRS)-Université de Lorraine (UL), and Laboratory of Polymeric and Composite Materials (LPCM), University of Mons-Hainaut, Mons, Belgium

Subjects
Aqueous solution, Polymers and Plastics, Silylation, Organic Chemistry, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Ring-opening polymerization, 6. Clean water, 0104 chemical sciences, Silyl ether, Inorganic Chemistry, chemistry.chemical_compound, [CHIM.POLY]Chemical Sciences/Polymers, Polymerization, chemistry, Polymer chemistry, Amphiphile, Materials Chemistry, Copolymer, [CHIM]Chemical Sciences, Solubility, 0210 nano-technology, ComputingMilieux_MISCELLANEOUS
Abstract

International audience; A large variety of amphiphilic polylactide-grafted dextrans has been synthesized with controlled architecture through a three-step procedure: partial protection of the dextran hydroxyl groups by silylation; ring-opening polymerization of D,L-lactide initiated from remaining hydroxyl groups on partially silylated dextran; and silyl ether deprotection under very mild conditions. Throughout the synthesis, detailed characterizations of each step led to the control of copolymer architecture in terms of graft number and lengths of graft and backbone. Depending on their proportion in polylactide, these copolymers were either water-soluble or soluble in organic solvents. The potential of these amphiphilic grafted copolymers as surfactants was estimated. Their organization at air/water or dichloromethane/water interfaces was investigated by interfacial tension measurements. Self-organization in water or toluene was evaluated using fluorescence spectroscopy. Depending on its solubility, each copolymer showed noticeable surfactant properties and was able to produce either hydrophobic or hydrated microdomains in water or toluene solutions, respectively

Published
2004

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