Accueil >
Production scientifique
Matière Molle
(422) Articles dans des revues
|
|
Translational viscous drags of an ellipsoid straddling an interface between two fluids
Auteur(s): Boniello G., Stocco A., Gross M., In M., Blanc C., Nobili M.
(Article) Publié:
Physical Review E: Statistical, Nonlinear, And Soft Matter Physics, vol. 94 p.012602 (2016)
Ref HAL: hal-01355947_v1
DOI: 10.1103/PhysRevE.94.012602
WoS: WOS:000379724600011
Exporter : BibTex | endNote
8 Citations
Résumé: We study the dynamics of individual polystyrene ellipsoids of different aspect ratios trapped at the air-water interface. Using particle tracking and in situ vertical scanning interferometry techniques we are able to measure translational drags and the protrusion in air of the ellipsoids. We report that translational drags on the ellipsoid are unexpectedly enhanced: despite the fact that a noticeable part of the ellipsoid is in air, drags are found larger than the bulk one in water.
|
|
|
Origin of Invariant Gel Melting Temperatures in the c-T Phase Diagram of an Organogel
Auteur(s): Christ Elliot, Blanc C., Al Ouahabi Abdelaziz, Maurin D., Le Parc R., Bantignies J.-L., Guenet Jean-Michel, Collin Dominique, Mesini Philippe J.
(Article) Publié:
Langmuir, vol. 32 p.4975-4982 (2016)
Texte intégral en Openaccess :
Ref HAL: hal-01344912_v1
DOI: 10.1021/acs.langmuir.6b00995
WoS: WOS:000376223800033
Exporter : BibTex | endNote
10 Citations
Résumé: Binary c–T phase diagrams of organogelators in solvent are frequently simplified to two domains, gel and sol, even when the melting temperatures display two distinct regimes, an increase with T and a plateau. Herein, the c–T phase diagram of an organogelator in solvent is elucidated by rheology, DSC, optical microscopy, and transmitted light intensity measurements. We evidence a miscibility gap between the organogelator and the solvent above a threshold concentration, cL. In this domain the melting or the formation of the gel becomes a monotectic transformation, which explains why the corresponding temperatures are nonvariant above cL. As shown by further studies by variable temperature FTIR and NMR, different types of H-bonds drive both the liquid–liquid phase separation and the gelation.
|
|
|
Small angle neutron scattering contrast variation reveals heterogeneities of interactions in protein gels
Auteur(s): Banc A., Charbonneau C., Dahesh M., Appavou Marie-Sousai, Fu Zhendong, Morel Marie-Hélène, Ramos L.
(Article) Publié:
Soft Matter, vol. 12 p.5340-5352 (2016)
Texte intégral en Openaccess :
Ref HAL: hal-01317647_v1
Ref Arxiv: 1605.05867
DOI: 10.1039/c6sm00710d
WoS: 000378934400011
Ref. & Cit.: NASA ADS
Exporter : BibTex | endNote
11 Citations
Résumé: The structure of model gluten protein gels prepared in ethanol/water is investigated by small angle X-ray (SAXS) and neutrons (SANS) scattering. We show that gluten gels display radically different SAXS and SANS profiles when the solvent is (at least partially) deuterated. The detailed analysis of the SANS signal as a function of the solvent deuteration demonstrates heterogeneities of sample deuteration at different length scales. The progressive exchange between the protons (H) of the proteins and the deuteriums (D) of the solvent is inhomogeneous and 60 nm large zones that are enriched in H are evidenced. In addition, at low protein concentration, in the sol state, solvent deuteration induces a liquid/liquid phase separation. Complementary biochemical and structure analyses show that the denser protein phase is more protonated and specifically enriched in glutenin, the polymeric fraction of gluten proteins. These findings suggest that the presence of H-rich zones in gluten gels would arise from the preferential interaction of glutenin polymers through a tight network of non-exchangeable intermolecular hydrogen bonds.
|
|
|
Nanocomposites with both structural and porous hierarchy synthesized from Pickering emulsions
Auteur(s): Avendano Carlos, Brun Nicolas, Mourad Eleonore, Fontaine Olivier, Sarroste Christine Labrugere, Baccour Mohamed, In M., Mehdi Ahmad, Stocco A., Vioux Andre
(Article) Publié:
New Journal Of Chemistry, vol. 40 p.4344-4350 (2016)
Ref HAL: hal-01329849_v1
DOI: 10.1039/c5nj03248b
WoS: WOS:000375586400041
Exporter : BibTex | endNote
3 Citations
Résumé: Commercial carboxymethylcellulose was used to prepare dispersible multi-walled carbon nanotubes-based composites. These composites were employed to prepare Pickering oil-in-water emulsions. Emulsion-templated macroporous materials were then prepared by embedding the oil droplets into a polymer resin arising from the polycondensation of furfural and phloroglucinol within the continuous aqueous phase in the presence of FeCl3 as catalyst. Polymerization afforded organic–inorganic nanocomposite materials in the form of capsules. After pyrolysis, highly microporous, magnetic and electrically conductive micrometric capsules could be obtained. This approach opens interesting prospects for catalysis, separation and electrochemistry applications.
|
|
|
Multiwalled Carbon Nanotube/Cellulose Composite: From Aqueous Dispersions to Pickering Emulsions
Auteur(s): Avendano Carlos, Brun Nicolas, Fontaine Olivier, In M., Mehdi Ahmad, Stocco A., Vioux Andre
(Article) Publié:
Langmuir, vol. 32 p.3907-3916 (2016)
Ref HAL: hal-01324784_v1
DOI: 10.1021/acs.langmuir.6b00380
WoS: WOS:000375243300012
Exporter : BibTex | endNote
12 Citations
Résumé: A mild and simple way to prepare stable aqueous colloidal suspensions of composite particles made of a cellulosic material (Sigmacell cellulose) and multiwalled carbon nanotubes (MWCNTs) is reported. These suspensions can be dried and redispersed in water at pH 10.5. Starting with rather crude initial materials, commercial Sigmacell cellulose and MWCNTs, a significant fraction of composite dispersed in water could be obtained. The solid composites and their colloidal suspensions were characterized by electronic microscopy, thermal analyses, FTIR and Raman spectroscopy, X-ray photoelectron spectroscopy, X-ray diffraction, and light scattering. The composite particles consist of tenuous aggregates of CNTs and cellulose, several hundred nanometers large, and are composed of 55 wt % cellulose and 45 wt % CNTs. Such particles were shown to stabilize cyclohexane-in-water emulsions. The adsorption and the elasticity of the layer they form at interface were characterized by the pendant drop method. The stability of the oil-in-water emulsions was attributed to the formation of an elastic network of composite particles at interface. Cyclohexane droplet diameters could be tuned from 20 to 100 μm by adjusting the concentration of composite particles. This behavior was attributed to the limited coalescence phenomenon, just as expected for Pickering emulsions. Interestingly, cyclohexane droplets were stable over time and sustained pH modifications over a wide range, although acidic pH induced accelerated creaming. This study points out the possibility of combining crude cellulose and MWCNTs through a simple process to obtain colloidal systems of interest for the design of functional conductive materials.
|
|
|
Structure of alumina-silica nanoparticles grafted with alkylphosphonic acids in poly(ethylacrylate) nanocomposites
Auteur(s): Schmitt Pauly Céline, Genix A.-C., Alauzun Johan G., Jestin Jacques, Sztucki Michael, Mutin P. Hubert, Oberdisse J.
(Article) Publié:
Polymer, vol. 97 p.138-146 (2016)
Ref HAL: hal-01317973_v1
DOI: 10.1016/j.polymer.2016.04.073
Exporter : BibTex | endNote
Résumé: Alumina-coated silica nanoparticles (NPs) grafted with phosphonic acids of different hydrophobicitywere used as filler in poly(ethylacrylate) nanocomposites. Phosphonic acids bearing short alkyl chains ora diethylene glycol group have been grafted at densities up to 3.2 P/nm2 on NPs (20 nm) dispersed inwater. Nanocomposites at particle fractions up to 10 vol% have been formulated by casting from thecolloidal mixtures of modified NPs and nanolatex in water. The dispersion of the NPs in the polymermatrix has been studied by TEM combined with small-angle scattering, evidencing aggregation of NPs.TEM shows micrometer-scale inhomogeneities depending on the surface/polymer matrix compatibility.For the local interparticle correlations, a quantitative analysis of the intensity based on the mapping ontothe effective structure factor of polydisperse hard spheres is developed. This mapping allows the modelfreedetermination of the internal volume fraction of aggregates, termed compacity k, to between 10%and 30%, compatible with the TEM analysis. k is found to increase for the higher particle volume fractions,to decrease with grafting density, and to be mostly independent of the nature and mass of thegraft. Preliminary evidence for an improved compatibility of grafted with respect to bare NPs is found, asopposed to their aqueous precursor suspensions where some pre-aggregation is induced by grafting.
|
|
|
Revealing nanocomposite filler structures by swelling and small-angle X-ray scattering
Auteur(s): Baeza G., Genix A.-C., Paupy-Peyronnet Nathalie, Degrandcourt Christophe, Couty Marc, Oberdisse J.
(Article) Publié:
Faraday Discussions, vol. 186 p.295 (2016)
Ref HAL: hal-01307989_v1
DOI: 10.1039/C5FD00117J
WoS: 000374440100019
Exporter : BibTex | endNote
13 Citations
Résumé: Polymer nanocomposites are used widely, mainly for the industrial application of car tyres. The rheological behavior of such nanocomposites depends in a crucial way on thedispersion of the hard filler particles – typically silica nanoparticles embedded in a soft polymer matrix. It is thus important to assess the filler structure, which may be quitedifficult for aggregates of nanoparticles of high polydispersity, and with strong interactions at high loading. This has been achieved recently using a coupled TEM/SAXSstructural model describing the filler microstructure of simplified industrial nanocomposites with grafted or ungrafted silica of high structural disorder. Here, wepresent an original method capable of reducing inter-aggregate interactions by swelling of nanocomposites, diluting the filler to low-volume fractions. Note that this isimpossible to reach by solid mixing due to the large differences in viscoelasticity between the composite and the pure polymer. By combining matrix crosslinking,swelling in a good monomer solvent, and post-polymerization of these monomers, it isshown that it is possible to separate the filler into small aggregates. The latter have then been characterized by electron microscopy and small-angle X-ray scattering,confirming the conclusions of the above mentioned TEM-SAXS structural model applied directly to the highly loaded cases.
|