Destribats M., Lapeyre V., Sellier E., Leal Calderon F., Ravaine V., Schmitt V.,
Langmuir 2012, 28, 3744-3755.

We used soft microgels made of poly(N-isopropylacrylamide) (pNIPAM) of variable cross-linking degrees and the same colloidal size to stabilize oil-in-water Pickering emulsions. The extent of droplet flocculation increased and the resistance of the emulsions to mechanical stresses decreased as the cross-linking density was augmented. Large flat films were separating the droplets, and we could measure the adhesion angle at the junction with the free interfaces through several microscopy methods. The size of the flat films and the values of the angles were reflecting strong adhesive interactions between the interfaces as a result of microgel bridging. In parallel, cryo-SEM imaging of the thin films allowed a precise determination of their structure. The evolution of the adhesion angle and of the film structure as a function of microgels cross-linking density provided interesting insights into the impact of particle softness on film adhesiveness and emulsion stability. We exploited our main findings to propose a novel route for controlling the emulsions end-use properties (flocculation and stability). Owing to particle softness and thermal sensitivity, the interfacial coverage was a path function (it depended on the sample “history”). As a consequence, by adapting the emulsification conditions, the interfacial monolayer could be trapped in a very dense and rigid configuration, providing improved resistance to bridging flocculation and to flow-induced coalescence.

 

Langmuir2012 p3744 TOC

La Chimie au Service d’une Délivrance de l’Insuline en Boucle Fermée
mercredi 19 décembre 2012
Messager L., Ancla C., Lapeyre V., Ravaine V., Catargi B.Médecine Clinique Endocrinologie et Diabète 2012, 59, 38-45.  
Indirect Bipolar Electrodeposition
mardi 27 novembre 2012
Loget G., Roche J., Gianessi E., Bouffier L., Kuhn A.,J. Am. Chem.Soc. 2012, 134, 20033-20036. Based on the principles of bipolar electrochemistry, localized pH gradients are generated at the surface of conducting particles in solution. This allows the toposelective deposition of inorganic and organic polymer layers via a pH-triggered precipitation mechanism. Due to the intrinsic symmetry... Read More...
Light-Emitting Electrochemical Swimmers
lundi 8 octobre 2012
Sentic M., Loget G., Manojlovic D., Kuhn A., Sojic N.,Angew. Chem. Int. Ed. 2012, 51, 11284–11288. Swimmer in the dark: Propulsion of a conducting object is intrinsically coupled with light emission using bipolar electrochemistry. Asymmetric redox activity on the surface of the swimmer (black bead; see picture) causes production of gas bubbles to propel the swimmer in a glass tube with... Read More...
Controlled Orientation of Asymmetric Copper Deposits on Carbon Microobjects by Bipolar Electrochemistry
mercredi 19 septembre 2012
Fattah Z., Garrigue P., Lapeyre V., Kuhn A., Bouffier L.,J. Phys. Chem. C 2012, 116, 22021-22027. Asymmetric particles of various chemical compositions have attracted great attention because of their application potential in different areas, ranging from photosplitting of water to autonomous swimmers. In this context, the spatial arrangement of the different components can be of major importance.... Read More...
Quantification of Photoelectrogenerated Hydroxyl Radical on TiO2 by Surface Interrogation Scanning Electrochemical Microscopy
mardi 7 août 2012
Zigah D., Rodriguez-Lopez P., Bard A. J.,Phys. Chem. Chem. Phys. 2012, 14, 12764-12772. Asymmetric particles of various chemical compositions have attracted great attention because of their application potential in different areas, ranging from photosplitting of water to autonomous swimmers. In this context, the spatial arrangement of the different components can be of major importance. We report... Read More...
Development of Functionalized Cyclotriveratrylene Analogues: Introduction of Withdrawing and p-Conjugated Groups
lundi 30 juillet 2012
Peyrard L., Dumartin M.-L., Chierici S., Pinet S., Jonusauskas G., Meyrand P., Gosse I.,J. Org. Chem. 2012, 77, 7023-7027. Cyclotriveratrylene analogues (CTVs) are supramolecular bowl-shaped molecules known for their ability to complex organic and organometallic guests, to form liquid crystals, polymers, or nanostructures. In this Article, we report the synthesis of new cyclotriveratrylene... Read More...
Electrochemistry and Bioactivity Relationship of 6-Substituted-4H-Pyrido[4,3,2-kl]acridin-4-one Antitumor Drug Candidates
vendredi 27 juillet 2012
Bouffier L., Gosse I., Demeunynck M., Mailley P.,Bioelectrochemistry 2012, 88, 103-109. We report here the electrochemical characterization of eight synthetic DNA intercalators based on the 4H-pyrido[4,3,2-kl]acridin-4-one structure. We found that the electrochemical behavior of these redox active drugs is strongly influenced by the nature of the solvent. A single two-electron reduction is... Read More...
True Bulk Synthesis of Janus Objects by Bipolar Electrochemistry
lundi 16 juillet 2012
Loget G., Roche J., Kuhn A.,Adv. Mater. 2012, 24, 5111-5116. Cover article Janus particles have different features/chemistry on two opposite sides (see figure). So far, they have been obtained mainly by two-dimensional synthetic methods, which are able to break the symmetry but limit the amount of produced particles. A true bulk approach, based on bipolar electrochemistry, is presented that... Read More...
Direct Visualization of Symmetry Breaking during Janus Nanoparticle Formation
mardi 3 juillet 2012
Loget G., Lee T.-C., Taylor R. W., Mahajan S., Nicoletti O., Jones S. T., Coulston R. J., Lapeyre V., Garrigue P., Midgley P. A., Scherman O. A., Baumberg J. J., Kuhn A.,Small 2012, 8, 2698-2703. The straight-forward synthesis of Janus nanoparticles composed of Ag and AgBr is reported. For their formation, cucurbit[n]uril (CB)-stabilized AgBr nanoparticles are first generated in water by... Read More...
Combined Macro/mesoporous Microelectrode Arrays (MEAs) for Low Noise Extracellular Recording of Neural Networks
mercredi 27 juin 2012
Heim M., Rousseau L., Reculusa S., Urbanova V., Mazzocco C., Joucla S., Bouffier L., Vytras K., Bartlett P., Kuhn A., Yvert B.Journal of Neurophysiology 2012, 15, 1793-1803. Microelectrode arrays (MEAs) are appealing tools to probe large neural ensembles and build neural prostheses. Microelectronics microfabrication technologies now allow building high-density MEAs containing several hundreds of... Read More...
Bulk Synthesis of Janus Objects and Asymmetric Patchy Particles
jeudi 10 mai 2012
Loget G., Kuhn A.,J. Mater. Chem. 2012, 22, 15457-15474. Feature article This review article highlights the most recent advances with respect to the preparation of Janus objects by bulk phase processes. Historically most of the concepts developed for generating asymmetric particles have been based on the use of interfaces or surfaces, which are necessary to break the symmetry. This restricts in... Read More...
Bipolar Electrochemistry for Cargo-lifting in Fluid Channels
mercredi 15 février 2012
Loget G., Kuhn A.,Lab on a Chip 2012, 12, 1967-1971. Hot Paper, Cover Article We report for the first time the vertical propulsion of conducting beads in liquid filled capillaries by bipolar electrochemistry. The beads, when exposed to an external electric field, act as bipolar electrodes showing hydroquinone oxidation on one side and proton reduction on the other side. The related asymmetric... Read More...
Origin and Control of Adhesion between Emulsion Drops Stabilised by Thermally-sensitive Soft Colloidal Particles
vendredi 20 janvier 2012
Destribats M., Lapeyre V., Sellier E., Leal Calderon F., Ravaine V., Schmitt V.,Langmuir 2012, 28, 3744-3755. We used soft microgels made of poly(N-isopropylacrylamide) (pNIPAM) of variable cross-linking degrees and the same colloidal size to stabilize oil-in-water Pickering emulsions. The extent of droplet flocculation increased and the resistance of the emulsions to mechanical stresses...
Site Selective Generation of Sol-gel Deposits in Layered Bi-metallic Macroporous Electrode Architectures
jeudi 19 janvier 2012
Lalo H., Bon Saint-Côme Y., Plano B., Etienne M., Walcarius E., Kuhn A.,Langmuir 2012, 28, 2323-2326. The elaboration of an original composite bimetallic macroporous electrode containing a site-selective sol–gel deposit is reported. Regular colloidal crystals, obtained by a modified Langmuir–Blodgett approach, are used as templates for the electrogeneration of the desired metals in the form... Read More...
The Fraction of Alpha-linolenic Acid present in the sn-2 position of Structured Triacylglycerols decreases in Lymph Chylomicrons and Plasma Triacylglycerols during the Course of Lipid Absorption in Rats
mercredi 30 novembre 2011
Couedelo L., Vaysse C., Vaique E., Guy A., Gosse I., Durand T., Pinet S., Cansell M., Combe N.Journal of Nutrition 2012, 142, 70-75. Little is known about the ability of α-linolenic acid (Ln) to remain in the sn-2 position of TG during the absorption process. The goal of this study was to determine the Ln distribution in the lymph (Study 1) and plasma (Study 2) TG of rats fed a single i.g. load... Read More...
Engineering of Complex Macroporous Materials through Controlled Electrodeposition in Colloidal Superstructures
mardi 29 novembre 2011
Heim M., Reculusa S., Ravaine S., Kuhn A.,Adv. Funct. Mater. 2012, 22, 538-545. Inside Cover Article Macroporous materials with a sophisticated architecture are obtained by electrochemical deposition of gold or polypyrrole in colloidal-crystal templates. The Langmuir–Blodgett technique enables assembly of sub-micrometric silica-particle monolayers on conductive gold substrates, thus leading to... Read More...
Electrochemical Investigations of Dissolved and Surface Immobilised 2-Amino-1,4-Naphthoquinones in Aqueous Solutions
samedi 29 octobre 2011
Bouffier L., Lister K. E., Higgins S. J., Nichols R. J., Doneux T.,J. Electroanal. Chem. 2012, 664, 80-87. The electrochemistry of proton coupled electron transfer phenomena is an important contemporary topic in molecular and interfacial electrochemistry, due to its significance in important organic and bioelectrochemical processes. We report here on the synthesis, self-assembly and... Read More...
Nanostructuration Strategies to Enhance Microelectrode Array (MEA) Performance for Neuronal Recording and Stimulation
mardi 18 octobre 2011
Heim M., Yvert B., Kuhn A.,J. Physiology - Paris 2012, 106, 137-145. Microelectrode arrays (MEAs) are widely used tools for recording and stimulating extracellular neuronal activity. Major limitations when decreasing electrode size in dense arrays are increased noise level and low charge injection capability. Nanostructuration of the electrode sites on MEAs presents an efficient way to overcome... Read More...