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International audience; Hypothesis: According to the so-called colloidal tectonic concept, we assumed that a single self-complementary polymer-based tecton could be used to design self-assembled emulsions. The polymer must be of high-molecular weight with balanced bipolar properties generating those of rigidity and flexibility. Linear polyethyleneimine (LPEI, 25 kDa) was used because it acts as a buffer by continuous protonation/deprotonation of the amine groups.Experiments: The relationships between the physicochemical properties of LPEI (protonation, charge, size, aggregation and gelation) and emulsions (type, droplet size, rheological behavior and stability) were investigated to highlight the self-assembly and stabilization mechanisms during the construction events as well as the inherent properties of emulsions (responsiveness to external stimuli).Findings: In aqueous solution, after a first heat and cool cycle, the adequate and spontaneous self-assembly of hydrophobic and hydrophilic sections leads to hydrogels by the formation of a 3D network where the crystallized hydrophobic domains act as knots. In the presence of various oils, the hydrogels provide long-term stable Pickering emulgels. The as-prepared emulsions are highly controllable due to their self-assembled nature (up to 10 consecutive runs). Consequently, this new approach provides a facile route to construct self-assembled, reversible and dynamics Pickering-like emulsions by simplifying the colloidal tectonics concept.

International audience; A predictive tool called COSMO-RS, Conductor-Like Screening Model for Real Solvents, based on quantum chemistry, dielectric continuum models, electrostatics surface interactions, and statistical thermodynamics, has been used to predict five key physicochemical properties of raw materials used in perfumery industries. The prediction of boiling point (BP), octanol-water partition coefficient (log P), vapor pressure (VP), water solubility (WS), and Henry's law constant (HLC) of fragrance molecules has been validated with a reference data set of 166 organic compounds. Knowing these properties for a fragrance molecule is essential and being able to predict them precisely can be particularly useful in the development of new molecules or in the replacement of controversial molecules regarding safety issues without compromising the overall hedonic accord. Finally, mapping the vapor pressure versus the Henry's law constant and the octanol-water partition coefficient consistently predicts the note class of the molecules useful for release comparison of captives.

The solubilization of fatty acids by small amphiphiles such as butyl ethylene glycol, butyl or pentyl diethylene glycol, and hexyl triethylene glycol, also called hydrotropes, was demonstrated by t...

This work reports a novel and visual method for the simultaneous determination of the chemical (kr ) and the physical (kq ) quenching rate constants of singlet oxygen (1 O2 ,1 ∆g ) in aqueous media. It is based on the disruption, by a water-soluble substrate S, of the 1 O2 chemiluminescence (CL) generated by the H2 O2 /Na2 MoO4 catalytic system. A mathematical analysis of the CL signal at 1270 nm vs time provides separately the overall (kr + kq ) and the chemical (kr ) quenching rate constants. In ordinary water (H2 O), 1 O2 lifetime is short and the CL intensity is weak allowing solely the investigation of very reactive substrates for which (kr + kq ) > 3 × 106 m-1 s-1 while, in D2 O, 1 O2 lifetime is significantly longer lifetime and the CL signal is much stronger allowing the study of poorly reactive substrates for which (kr + kq ) > 4 × 105 m-1 s-1 . The method has been successfully tested on a series of anionic and nonionic water-soluble naphthalene derivatives commonly used as bio-compatible 1 O2 carriers. The obtained kr and kq values are in good agreement with the values determined by conventional techniques, namely, flash photolysis and competitive kinetics with a reference quencher.

We present the development of surfactant‐free, silica‐free and fully biobased oil‐in‐water antimicrobial Pickering emulsions, based on the self‐assembly of b ‐cyclodextrin and phytoantimicrobial oils (terpinen‐4‐ol or carvacrol). Undecylenic acid (UA), derived from castor oil, can be used as bio‐based drug to treat fungal infection, but is less effective than petroleum‐based drugs as azole derivatives. To maximize its antifungal potential, we have incorporated UA in fully biobased Pickering emulsions. These emulsions are effective against fungi, Gram‐positive and Gram‐negative bacteria. The carvacrol emulsion charged with UA is +390 % and +165 % more potent against methicillin‐resistant S. aureus (MRSA), compared to UA and azole‐based commercial formulations. Moreover, this emulsion is up to +480 % more efficient that UA ointment against C. albicans . Finally, remarkable eradication of E. coli and MRSA biofilms was obtained with this environmental‐friendly emulsion.

Rosemary (Rosmarinus officinalis L.) is a Mediterranean herb known for its high antioxidant power that has been widely attributed to carnosic acid (CA). Passive extractions of CA have been performed in water by using five commercially available short-chain alkyl polyglycosides (APG) with alkyl chain lengths ranging from 4 to 10 carbon atoms and polar heads composed of pentoses and/or glucoses. APGs are nontoxic amphiphiles with high biodegradability. Their solubilizing capacity for CA has been determined, highlighting heptyl glucoside (C₇Glu) as the most efficient one, followed by 2-ethylhexyl glucoside (C₆,–₂Glu) and isoamyl xyloside (iC₅Xyl). However, iC₅Xyl exhibited the highest selectivity toward CA solubilization as compared to ursolic acid (UA), a potential coextracted compound of rosemary leaves. In addition, it was found to be the most efficient amphiphile to extract CA from both ground and whole rosemary leaves. To optimize the maceration process and the recovery of the extract, a full factorial design 2⁴ was performed investigating iC₅Xyl concentration, temperature, stirring, and extraction time. A high concentration of hydrotrope was found to be the most important condition to optimize the maceration step, while the temperature particularly increases the yield, but in detriment of the CA content in the final dried extract.

International audience; The hydrophobicity of oils is a key parameter to design surfactant/oil/water (SOW) macro-, micro-, or nano-dispersed systems with the desired features. This essential physicochemical characteristic is quantitatively expressed by the equivalent alkane carbon number (EACN) whose experimental determination is tedious since it requires knowledge of the phase behavior of the SOW systems at different temperatures and for different surfactant concentrations. In this work, two mathematical models are proposed for the rapid prediction of the EACN of oils. They have been designed using artificial intelligence (machine-learning) methods, namely, neural networks (NN) and graph machines (GM). While the GM model is implemented from the SMILES codes of a 111-molecule training set of known EACN values, the NN model is fed with some σ-moment descriptors computed with the COSMOtherm software for the 111-molecule set. In a preliminary step, the leave-one-out algorithm is used to select, given the available data, the appropriate complexity of the two models. A comparison of the EACNs of liquids of a fresh set of 10 complex cosmetic and perfumery molecules shows that the two approaches provide comparable results in terms of accuracy and reliability. Finally, the NN and GM models are applied to nine series of homologous compounds, for which the GM model results are in better agreement with the experimental EACN trends than the NN model predictions. The results obtained by the GMs and by the NN based on σ-moments can be duplicated with the demonstration tool available for download as detailed in the Supporting Information.

International audience; Emollient oils are ubiquitous ingredients of personal care products, especially skin care and hair care formulations. They offer excellent spreading properties and give end-use products a soft, pleasant and non-sticky after-feel. Emollients belong to various petro- or bio-based chemical families among which silicone oils, hydrocarbons and esters are the most prominent. Silicones have exceptional physicochemical and sensory properties but their high chemical stability results in very low biodegradability and a high bioaccumulation potential. Nowadays, consumers are increasingly responsive to environmental issues and demand more environmentally friendly products. This awareness strongly encourages cosmetics industries to develop bio-based alternatives to silicone oils. Finding effective silicon-free emollients requires understanding the molecular origin of emollience. This review details the relationships between the molecular structures of emollients and their physicochemical properties as well as the resulting functional performances in order to facilitate the design of alternative oils with suitable physicochemical and sensory properties. The molecular profile of an ideal emollient in terms of chemical function (alkane, ether, ester, carbonate, alcohol), optimal number of carbons and branching is established to obtain an odourless oil with good spreading on the skin. Since none of the carbon-based emollients alone can imitate the non-sticky and dry feel of silicone oils, it is judicious to blend alkanes and esters to significantly improve both the sensory properties and the solubilizing properties of the synergistic mixture towards polar ingredients (sun filters, antioxidants, fragrances). Finally, it is shown how modelling tools (QSPR, COSMO-RS and neural networks) can predict in silico the key properties of hundreds of virtual candidate molecules in order to synthesize only the most promising whose predicted properties are close to the specifications.

Carnosic acid (CA) is a hydrophobic secondary metabolite and the main antioxidant of rosemary. Extractions of CA from whole leaves of rosemary have been performed with aqueous solutions of twelve s...

Amphiphilic gradient copolymers represent a promising alternative to extensively used block copolymers due to their facile one-step synthesis by statistical copolymerization of monomers of different reactivity. Herein, an in-depth analysis is provided of micelles based on amphiphilic gradient poly(2-oxazoline)s with different chain lengths to evaluate their potential for micellar drug delivery systems and compare them to the analogous diblock copolymer micelles. Size, morphology, and stability of self-assembled nanoparticles, loading of hydrophobic drug curcumin, as well as cytotoxicities of the prepared nanoformulations are examined using copoly(2-oxazoline)s with varying chain lengths and comonomer ratios. In addition to several interesting differences between the two copolymer architecture classes, such as more compact self-assembled structures with faster exchange dynamics for the gradient copolymers, it is concluded that gradient copolymers provide stable curcumin nanoformulations with comparable drug loadings to block copolymer systems and benefit from more straightforward copolymer synthesis. The study demonstrates the potential of amphiphilic gradient copolymers as a versatile platform for the synthesis of new polymer therapeutics. acceptedVersion

International audience; In the present work, meglumine, an aminocarbohydrate derived from glucose with a secondary amine group, was found to be able to increase the water-solubility of the well-known and beneficial flavonoid quercetin. pH proves to be a fundamental factor for this purpose. The solubility enhancement as a function of the pH as well as the mechanism behind this phenomenon were investigated. The state of charge of quercetin depending on pH has been estimated from the calculation of the pKa by COSMO-RS. A compromise between a satisfying solubility enhancement (6–7-fold) and reasonable stability against oxidation (70–75 % of quercetin still intact after 2 h) was found around pH 8. The solubilization mechanism is believed to be based on proton exchange between quercetin and the amine function of meglumine, and on the ability of meglumine to form numerous hydrogen bonds with water molecules through its five hydroxyl groups. Finally, it is shown that the underlying solubilization mechanism can be extended both to other polyphenols and to other hydrotropes.

International audience; This manuscript provides an understanding of the emulsification mechanisms of a model alkane (dodecane) in concentrated aqueous sodium silicate solutions, for e.g. formulating alkane/geopolymer composites for varied applications. To this purpose, we assume that silicate oligomers stabilize the emulsion by positioning themselves at the interface between alkane/aqueous solution. Moreover, the addition of an alkyltrimethylammonium, which interacts with silicate oligomers, is assumed to favor their positioning at the interface to increase the stability of the emulsion by Pickering effect. First, we study the influence of sodium silicate and hydroxide concentrations with up to 6 mol⋅L-1 (NaOH and SiO2) on the interfacial tension (γ) between dodecane and water. Secondly, we study the effect of CetylTrimethyl Ammonium Bromide (CTAB) and DecylTrimethylAmmonium Bromide (DeTAB) on the interfacial tension and the stability of the emulsion. Adding CTAB surfactant leads to partial precipitation but significantly decreases the interfacial tension to less than 4 mN.m-1. These effects that are not observed with DeTAB. The precipitate corresponds to CTAB-silicates and seems to contribute to the stabilization of the water/dodecane system, presumably through Pickering effect. Moreover, emulsion stability is shown to be related to the condensation/decondensation state of silicate species.

International audience; Dicarboxylic acids were prepared by the one-pot oxidative cleavage of cyclic alkenes with aqueous H2O2 by adsorbing dodecyltrimethylammonium phosphotungstate nanoparticles, and silica particles functionalized with octadecyl chains and sulfonic acid groups, C18/C3SO3H, at the W/O interface. Na2HPO4 and [C12]H2PO4 conditioned the interlocking and self-assembly of the particles, enhancing the catalytic selectivity, especially for cyclooctene.

This Review summarizes recent progress in liquid–liquid and gas–liquid dispersions stabilized by solid surface-active colloidal particles (emulsions, foams, bubbles, marbles, bijels) as microreactors. These new systems constitute original platforms for reengineering multiphase reactors towards a higher degree of sustainability.\ud \ud Pickering emulsions, foams, bubbles, and marbles are dispersions of two immiscible liquids or of a liquid and a gas stabilized by surface-active colloidal particles. These systems can be used for engineering liquid–liquid–solid and gas–liquid–solid microreactors for multiphase reactions. They constitute original platforms for reengineering multiphase reactors towards a higher degree of sustainability. This Review provides a systematic overview on the recent progress of liquid–liquid and gas–liquid dispersions stabilized by solid particles as microreactors for engineering eco-efficient reactions, with emphasis on biobased reagents. Physicochemical driving parameters, challenges, and strategies to (de)stabilize dispersions for product recovery/catalyst recycling are discussed. Advanced concepts such as cascade and continuous flow reactions, compartmentalization of incompatible reagents, and multiscale computational methods for accelerating particle discovery are also addressed.

International audience

This work reports a novel and visual method for the simultaneous determination of the chemical (k

An organosoluble ammonium molybdate salt catalytically converts allylic hydroperoxides of fatty acid methyl esters with good selectivities into either their corresponding alcohols or enones depending on the reaction conditions. Whereas a gentle heating of methyl oleate hydroperoxides in toluene at 80 °C mainly provides the enone in a 83/17 ratio, presence of triethylamine at 40 °C reverses this ratio to 7/93 in favor of the alcohol. Extension of the reaction scope to other alkenes like cyclohexene, cyclooctene, α- and β-pinenes, β-citronellol, and 2-octene shows the wide potential applications of the process which lead to relevant oxygenated building blocks, especially oils as a possible alternative of castor oil.

Alumina-functionalized ordered mesoporous silica SBA-15 particles have been proposed to stabilize Pickering emulsions. Functionalization of SBA-15 particles have been performed by depositing alumina using a two-step synthesis (first, silica condensation, followed by alumina precipitation). Three different Al to Si ratios have been prepared. The calcined materials have been characterized by TEM, SEM, XRD, N

Depuis l’avenement des vernis a ongles nitrocellulosiques dans les annees 30, le vernis a ongles est devenu un produit cosmetique commun et populaire aux couleurs et effets visuels tres varies. Il reste neanmoins un produit de formulation complexe devant posseder de hautes performances techniques prenant en compte a la fois les exigences du marche, de l’environnement et de l’Homme. La tâche est d’autant plus difficile que le nombre de matieres premieres autorisees diminue drastiquement avec une reglementation de plus en plus stricte. Cet article se concentre principalement sur les vernis a ongles solvantes, apres une partie sur la composition et la physicochimie de l’ongle

International audience; Supramolecular hybrid functional nanoparticles (NPs) can be obtained via the colloidal tectonics approach provided that multiple interactive molecular tectons are used. Herein, the programmable synthesis of novel hybrid core–shell nanoparticles via the following sequential steps is reported: (i) complexation of 1‐decanol by the β‐cyclodextrin (β‐CD), (ii) spontaneous self‐assembly into CD NPs, (iii) adsorption of polyoxometalate anions, PW12O403−, on the polar neutral interface of the CD NPs. Such an approach paves the way for the design of novel and original materials and systems.

A series of PEG-functionalized silica nanoparticles with various molecular weight (MW 200, 400, 550, 2000, 5000 g.mol−1) have been prepared through a one-step synthesis and further used for the elaboration of temperature-responsive Pickering. The physicochemical properties of the nanoparticles were determined by TEM, TGA, DLS, surface tension and zeta potential measurements and the formed emulsions have been characterized by optical microscopy. The ability of SiO2@mPEG 550 to form temperature-responsive emulsions with oils of different nature has been explained by the hydrophilic/hydrophobic balance of the PEG/mPEG chains. The emulsions stabilized with PEG-functionalized SiO2 NPs undergo a clear temperature-triggered destabilization from room temperature to 80 °C due to the modification of the distribution of the PEG/mPEG chain at the oil-water interface.

International audience; Poly(4-vinylpyridine) particles, P4VP, show a great potential from the environmental and economic perspective since they are cheap and extensively used for safer and greener organic syntheses. Moreover, their pH-sensitive properties would make it easy to obtain “on-off”, recyclable and reusable Pickering emulsions. The relationships between particle structures (size, shape, acidity and charge) and emulsion properties (type, droplet size and stability against environmental stresses) were investigated. The protonation increased the particles diameter to 147 nm compared to the pristine ones (88 nm) due to electrostatic repulsions which swell the particles. The ζ-potential was decreased with increasing acidity (from +60 to +30 mV) due to the accumulation of chlorides onto the surface. Thus, the acidic particles of 39 mmolH+/g and +57 mV were more effective in emulsifying heptane in water with long-term stability in storage conditions (up to one year) and unprecedented resistance against centrifugation and temperature (up to 5000 rpm and 60 °C). Nevertheless, destabilization can be easily achieved by pH or ionic strength changes facilitating the phase separation and the particles recovery. Contrary to the literature of responsive Pickering emulsions, which require relatively complex systems, the investigated one provides a simple route to obtain various “on-off” switches using P4VP cross-linked particles which possess changeable structures based on electrostatic repulsions. Consequently, the exploitation of such a system could be attractive in biphasic media in which the P4VP would act as a reagent, scavenger, and/or catalyst.

A series of 13 well-defined alkylglucuronamides [AGUA] surfactants with hydrophobic chains consisting of fatty alcohols (C8, C12, or C16) involved in a glucosidic bond has been synthesized in two steps from glucuronic acid or glucuronolactone. The nonionic polar heads are a sugar unit with an amide function derived from five different amines, i.e., methylamine, ammonia, ethanolamine, ethoxyethanolamine, and aminopropanediol. Their CMC values present variations from 0.03 to 29 mM, and their hydrophilic/lipophilic behaviors have been compared to conventional dodecyl polyethoxylated surfactants (C12Ej) using the PIT-slope methodology. They cover a large scale of the corresponding C12Ej with j varying from 5 to 8. Regarding functional properties, the novel alkylglucuronamides exhibit good foaming properties. Last but not least, two of them could be classified as easily biodegradable according to respirometric tests.

Hansen Solubility Parameters (HSP) have been shown to be an effective approach for rationalizing and predicting the stability of titanium dioxide nanoparticles (TiO2 NPs) dispersions. However, interparticle electrostatic interactions, not considered in Hansen’s approach but taken into account in the DLVO theory, are expected to play a significant role in organic solvents having a notable dielectric constant. Zeta potential ζ of TiO2 P25 NPs was measured in both aqueous and organic media to identify DLVO-stabilized dispersions from those stabilized by more specific NP-solvent interaction. Stability was quantified using a Turbiscan optical device which provides Stokes diameters and Relative Turbiscan Stability Index (RTSI). When the zeta potential of NPs and the dielectric constant of the solvent are both high, the dispersion benefits from additional stabilization while when the electrostatic repulsion is negligible, only the solvents within a Hansen dispersion sphere give stable dispersions. The two interpretations are therefore complementary to describe the behavior of TiO2 dispersions in organic solvents.

The autoxidation of FAMEs of colza, sunflower and linseed oils was studied at 40 °C under oxygen atmosphere at 150 kPa and was compared to that of mixtures of pure methyl oleate, linoleate and linolenate. Three steps corresponding to an induction time, an autocatalytic process and a pseudo steady-state could be distinguished and their kinetic constants were calculated for each oil. The influence of methyl linoleate on methyl oleate oxidation was determined at eight different ratios, highlighting that a 35/65 w/w composition corresponding to the sunflower one was a good compromise between oxidation time and minimization of methyl linoleate amount. Same approach was undertaken on this mixture to investigate the influence of methyl linolenate as a third constituent using pure ester and linseed oil FAMEs. A weight fraction of 15–20% was found to be optimal to favor the oxidation. Methyl linolenate has no influence on the relative disappearance of methyl linoleate versus methyl oleate. Hence, the most oxidizable composition with the lowest amount of the tri-unsaturated FAME is the ternary mixture methyl oleate/methyl linoleate/methyl linolenate = 29:53:18 ratio, which corresponds to a mixture of sunflower and linseed oils at a ≈ 60:40 ratio. This would be the best vegetable oil composition for alkyd resins.

The autoxidation of fatty acid methyl esters (FAMEs) derived from colza, sunflower, linseed and tung oils and the oxidation of sunflower FAMEs in the presence of several commercial driers based on Co(II), Mn(II), Fe(II), V(IV), Sr(II), Zr(IV), Ca(II), Zn(II) have been investigated. The oxidation step was studied through oxygen uptake measurements with an automatic O 2 pressure recorder (RapidOxy ® ) and by ATR-FTIR spectroscopy. Pure methyl linoleate hydroperoxides (ROOH) were prepared by photooxidation to follow their decomposition by HPLC in the presence of the driers. Only Co(II), Mn(II) and Fe(II) as primary driers have catalytic effects both on the oxidation and on the ROOH decomposition steps. However, the Co-based drier shows the higher oxidation rate while the Fe-based drier has the greater ROOH decomposition rate. On the other hand, oxidation runs faster by increasing the amount of driers from 2.5 to 25–50 mM but an antioxidant behavior is observed at higher levels. Secondary driers show poor or no catalytic activities both on the oxidation and the ROOH decomposition steps with a conversion ranging from 5 to 9% over 24 h. Combinations of driers were finally investigated to highlight possible synergistic or antagonist effects during the oxidation and hydroperoxides decomposition steps. Synergistic effects were found only on the oxidation stage with Co(II)-Zn(II), Mn(II)-Zn(II) and Fe(II)-Ca(II), while these latter do not have influence on the decomposition step.

The standard HLD (Hydrophilic-Lipophilic-Deviation) equation expressing quantitatively the deviation from the “optimum formulation” of Surfactant/Oil/Water systems is normalized and simplified into a relation including only the three more meaningful formulation variables, namely (i) the “Preferred Alkane Carbon Number” PACN which expresses the amphiphilicity of the surfactant, (ii) the “Equivalent Alkane Carbon Number” EACN which accurately reflects the hydrophobicity of the oil and (iii) the temperature which has a strong influence on ethoxylated surfactants and is thus selected as an effective, continuous and reversible scanning variable. The PACN and EACN values, as well as the “temperature-sensitivity-coefficient”τ of surfactants are determined by reviewing available data in the literature for 17 nonionic n-alkyl polyglycol ether (CiEj) surfactants and 125 well-defined oils. The key information used is the so-called “fish-tail-temperature” T* which is a unique data point in true ternary CiEj/Oil/Water fish diagrams. The PACNs of CiEj surfactants are compared with other descriptors of their amphiphilicity, namely, the cloud point, the HLB number and the PIT-slope value. The EACNs of oils are rationalized by the Effective-Packing-Parameter concept and modelled thanks to the COSMO-RS theory.

Les emollients sont omnipresents dans les produits de soin de la peau et du cheveu. Ils offrent d’excellentes proprietes d’etalement et apportent aux formulations un toucher doux, agreable, non collant. Toutefois, le consommateur se tourne de plus en plus vers des produits plus respectueux de l'Homme et de la planete ; l'industrie cosmetique se doit de proposer des alternatives aux huiles de silicone, emollients petrosources aux proprietes remarquables encore largement utilises. Cet article dresse un etat des lieux des connaissances des relations structure chimique – proprietes sensorielles de ces molecules. Il s’avere utile pour developper des alternatives innovantes aux silicones.

The standard HLD (Hydrophilic-Lipophilic-Deviation) equation expressing quantitatively the deviation from the "optimum formulation" of Surfactant/Oil/Water systems is normalized and simplified into a relation including only the three more meaningful formulation variables, namely (i) the "Preferred Alkane Carbon Number" PACN which expresses the amphiphilicity of the surfactant, (ii) the "Equivalent Alkane Carbon Number" EACN which accurately reflects the hydrophobicity of the oil and (iii) the temperature which has a strong influence on ethoxylated surfactants and is thus selected as an effective, continuous and reversible scanning variable. The PACN and EACN values, as well as the "temperature-sensitivity-coefficient"τ of surfactants are determined by reviewing available data in the literature for 17 nonionic n-alkyl polyglycol ether (C

Que ce soit a la maison ou en salon de coiffure, de nombreuses personnes se colorent les cheveux. Une large gamme de produits, aux palettes de couleurs tres variees et a l’utilisation aisee, est proposee aux consommateurs. Ils ont le choix entre des colorations capillaires permanentes, semi-permanentes ou temporaires. Le principal defi pour les formulateurs est de concilier beaute et respect du cheveu en developpant des produits inoffensifs et moins agressifs. Cet article decrit, dans un premier temps, le cheveu et le constituant responsable de sa couleur, la melanine, pour aborder ensuite les differents types de colorations capillaires ainsi que leur mode d’action.

The structure of a hexaisoindoline iron(III) complex reported in 1962 was corrected as the one of a recently described helmet phthalocyanine-like iron(III) complex. Accordingly, its catalytic activities were compared to commercial Co(II) and Fe(II) driers towards the oxidation of bulk FAMEs through oxygen uptake measurements and by ATR-FTIR spectroscopy, as well as its ability to decompose methyl linoleate hydroperoxides. It is shown that the phthalocyanine-like iron(III) complex presents higher catalytic performances at low concentrations and under mild conditions of temperature and pressure, both on the overall oxidation process and on the decomposition steps of the drying chemical process. The efficiency of the phthalocyanine-derived iron(III) complex was confirmed by the drying of an alkyd resin emulsion and a satin white paint formulation which exhibits a very good hardness and a low yellowing of the film.

Apparue en 1990, la technologie microfluidique a ouvert des voies de comprehension de differents phenomenes dans des disciplines variees. Elle a en meme temps permis de developper des nouveaux systemes complexes pour de nouvelles applications. Cet article etablit l’etat de l’art de la microfluidique dans le domaine des emulsions (simples, multiples, de Pickering) et des systemes colloidaux complexes (microcapsules, microgels, vesicules), en partant d’une description des generalites dans chaque domaine jusqu’a detailler certaines applications.

A series of 18 new biaryls has been synthesized and investigated with regard to their organocatalytic efficiency. They consist of a hydroquinone core linked to a phenol or a resorcinol moiety. It is shown that the resorcinol moiety substituted on its meta position has a strong impact on the catalytic activities of these compounds towards the reduction of dioxygen by diethylhydroxylamine (DEHA) in aqueous medium. While the derivative consisting of the two cores spaced by three methylene units is completely inactive, substitution on the hydroquinone part leads to tremendously active catalysts, especially the biaryl consisting of methoxyhydroquinone-orcinol. Two mechanisms are proposed to explain the dramatic efficiency of the novel hydroquinone-based biarylic polyphenols for the catalytic reduction of dioxygen, both considering the influence of the orcinol moiety on the semiquinone anion intermediate. As a first hypothesis, this substituent could promote its direct reduction by DEHA to regenerate the hydroquinone, which will react again to regenerate the semiquinone. On the other hand, an intramolecular hydrogen bond could enhance the reactivity of the semiquinone anion toward dioxygen by an addition–elimination mechanism. In this case, the elimination would provide the corresponding quinone but, since the reduction of the quinones by DEHA is much slower than the observed kinetics, a reduction by DEHA prior to the elimination has to be considered to generate the semiquinone anion instead of the quinone.

International audience; Silica nanoparticles have been designed by surface modification to stabilize solventless catalytic Pickering emulsions for effective biodiesel production. With respect to this, and based on full physicochemical characterization of both nanoparticles and emulsions, an optimum balance between inert (i.e., alkyl chains) and active (i.e., sulfonic acids) surface functional groups to obtain amphiphilic and catalytic properties was achieved with C18-SiO2-SO3H (C18 : SO3H molar ratio = 54 : 46 with a degree of grafting of 48%). Under optimal conditions, biphasic transesterification of several vegetable oils with methanol in the presence of these modified silica catalysts proceeds at competitive rates: the conversion of triglycerides is higher than 92% at 90 °C after 12 h. In addition, the catalytic system was not deactivated by the presence of free fatty acids in the crude feedstock and the nanoparticles could be repeatedly used at least 5 times without any loss of activity.

22 natural polyphenols are compared to 7 synthetic antioxidants including BHT, BHA, TBHQ and PG with regard to their ability to protect omega-3 oils from autoxidation. The antioxidant efficiency of phenols is assessed using the DPPH test and the measurement of oxygen consumption during the autoxidation of oils rich in omega-3 fatty acids. Also, the bond dissociation enthalpies (BDE) of the Ar-OH bonds are calculated and excellent correlations between thermodynamic, kinetic and oxidation data are obtained. It is shown that kinetic rates of hydrogen transfer, number of radicals scavenged per antioxidant molecule, BDE and formation of antioxidant dimers from the primary radicals play an important role regarding the antioxidant activity of phenols. Based on this, it is finally shown that myricetin, rosmarinic and carnosic acids are more efficient than α-tocopherol and synthetic antioxidants for the preservation of omega-3 oils.

Nosocomial infections have emerged as important causes of morbidity and mortality in immunocompromised individuals. In this respect, biocides are widely used in hospitals leading to resistant microorganisms. We show here that cyclodextrins can remarkably boost the virucidal activity of di-n-decyldimethylammonium chloride. These oligosaccharides synergistically work with the biocide affording a noticeable reduction of the active virucide concentration between 40 and 85%. Partial replacement of a significant amount of the biocide by eco- and bio-compatible cyclodextrins whilst maintaining the same activity is of great interest as it allows the reduction of the toxicological drawbacks of classical biocide mixtures.

Biobased surfactants were synthesized using poly(glycerol-succinate) as the polar head group and variable acyl groups as hydrophobic tails. Acyl chain lengths ranged from 8 to 14 carbon atoms. The resulting oligomeric surfactants were characterized by quantitative 13C nuclear magnetic resonance (NMR), acid values and size exclusion chromatography. Investigation of the physicochemical properties of the acyl poly(glycerol-succinate) surfactants revealed their potential for use in a wide array of applications. The acyl poly(glycerol-succinate) functional properties appeared to be particularly concentration-dependent. This study highlights the relative impact of acyl chain length on the polymeric structure, physicochemical and functional behaviors, and biodegradability of the acyl poly(glycerol-succinate) surfactants.

Seven new antioxidants derived from natural or synthetic phenols have been designed as alternatives to BHT and BHA antioxidants. Influence of various substituents at the ortho, meta and para positions of the aromatic core of phenols on the bond dissociation enthalpy of the ArO-H bond was evaluated using a DFT method B3LYP/6-311++G(2d,2p)//B3LYP/6-311G(d,p). This prediction highlighted the ortho-propenyl group as the best substituent to decrease the bond dissociation enthalpy (BDE) value. The rate constants of hydrogen transfer from these phenols to DPPH radical in a non-polar and non-protic solvent have been measured and were found to be in agreement with the BDE calculations. For o-propenyl derivatives from 2-tert-butyl-4-methylphenol, BHA, creosol, isoeugenol and di-o-propenyl p-cresol, fewer radicals were trapped by a single phenol molecule, i.e. a lower stoichiometric number. Reaction mechanisms involving the evolution of the primary phenoxyl radical ArO are proposed to rationalise these effects.

Formulation and process variables in surfactant/oil/water (SOW) systems can strongly modify the water/oil interfacial tension leading to different behaviors. Pre-equilibration time of the SDS/toluene/1-butanol/NaCl(aq) system was studied as a process variable and the flow regimes were described at different continuous and dispersed flow rates through a flow focusing geometry. Salinity and oil nature for the SDS/n-alkane/alcohol/NaCl(aq) equilibrated system were studied as formulation variables at fixed dispersed flow rates, changing the continuous flow rate and the formulation variable in order to get O/W or W/O emulsions in hydrophilic and hydrophobic chips, respectively. Pre-equilibration time modifies the flow regimes depending on the differences observed in the interfacial tension at t = 0 and t = 24 h of equilibration. Under very hydrophilic conditions, when γt=24 > γt=0, the entire droplet area is slightly higher for equilibrated systems. At WIII condition, when γt=0 >> γt=24, droplets are formed only in jetting regime for not equilibrated systems. For salinity scan, monodispersed oil droplets were obtained at low salinities, S = 0−0.25 % and in the oil scan, water droplets were obtained when using cyclohexane and cyclohexane-hexane mixtures. In both cases, flow regimes are reported into the formulation maps, using the Hydrophilic Lipophilic Deviation as formulation variable (HLD vs flow rate ratio). Droplet size was fitted into the same equation ( d i ≈ α C a c - 0.264 ), and it is noteworthy that the interfacial tension in CaC is lower than in most of reported works using flow-focusing geometries and both emulsions (W/O and O/W) were obtained with the same surfactant.

The human nail, like any biological material, is not readily available in large amounts and shows some variability from one individual to another. Replacing it by synthetic models is of great interest to perform reproducible and reliable tests in order to assess drug diffusion or nail lacquer adhesion for example. Keratin films, produced at the lab scale from natural hair, and the commercially available Vitro-nail® sheets have been proposed as models of human nails. In this study, we have investigated in detail these two materials. Surface aspect, composition, surface energy and water permeation were determined by SEM-EDS, ATR-FTIR, XPS, DVS and tensiometry and were compared to those of nails clippings. The development of a probe tack test using a rotational rheometer allowed us to measure the adhesion of three different nail lacquers on each substrate and the results were correlated with the surface state. It is shown that except roughness, keratin films exhibit similar composition, water sorption and surface energy as human nails. Vitro-nail® presents a more hydrophilic and permeable behavior than natural nail due to probable higher proportions of amide functions and absence of disulfide bridges. With the aim to improve nail lacquer residence, theimportance of adsorption, electrostatic and mechanical adhesions as well as water sorption behavior is highlighted and allowed to show the importance of roughness, a low surface energy, a moderate hydrophobicity and an ability to form hydrogen and electrostatic bonds in order to optimize adhesion. 131

International audience; The directed assembly of molecular building blocks into discrete supermolecules or extended supramolecular networks through noncovalent intermolecular interactions is an ongoing challenge in chemistry. This challenge may be overcome by establishing a hierarchy of intermolecular interactions that, in turn, may facilitate the edification of supramolecular assemblies. As noncovalent interactions can be used to accelerate the reaction rates and/or to increase their selectivity, the development of efficient and practical catalytic systems, using supramolecular chemistry, has been achieved during the last few decades. However, between discrete and extended supramolecular assemblies, the newly developed “colloidal tectonics” concept allows us to link the molecular and macroscopic scales through the structured engineering of colloidal structures that can be applied to the design of predictable, versatile, and switchable catalytic systems. The main cutting-edge strategies involving supramolecular chemistry and self-organization in catalysis will be discussed and compared in this review.