Destribats M., Lapeyre V., Sellier E., Leal-Calderon F., Schmitt V., Ravaine V.
Langmuir 2011, 27(23), 14096-14107

Emulsions were prepared using poly(N-isopropylacrylamide) microgels as thermoresponsive stabilizers. The latter are well-known for their sensitivity to temperature: they are swollen by water below the so-called volume phase transition temperature (VPTT = 33 °C) and shrink when heated above it. Most of the studies reported in the literature reveal that the corresponding emulsions are of the oil-in-water type (O/W) and undergo fast destabilization upon warming above the VPTT. In the present study, whereas O/W emulsions were obtained with a wide panel of oils of variable polarity and were all thermoresponsive, water-in-oil (W/O) emulsions were found only in the presence of fatty alcohols and did not exhibit any thermal sensitivity. To understand the peculiar behavior of emulsions based on fatty alcohols, we investigated the organization of microgels at the oil–water interface and we studied the interactions of pNIPAM microgels with octanol. By combining several microscopy methods and by exploiting the limited coalescence process, we provided evidence that W/O emulsions are stabilized by multilayers of nondeformed microgels located inside the aqueous drops. Such behavior is in contradiction with the empirical Finkle rule stating that the continuous phase of the preferred emulsion is the one in which the stabilizer is preferentially dispersed. The study of microgels in nonemulsified binary water/octanol systems revealed that octanol diffused through the aqueous phase and was incorporated in the microgels. Thus, W/O emulsions were stabilized by microgels whose properties were substantially different from the native ones. In particular, after octanol uptake, they were no longer thermoresponsive, which explained the loss of responsiveness of the corresponding W/O emulsions. Finally, we showed that the incorporation of octanol modified the interfacial properties of the microgels: the higher the octanol uptake before emulsification, the lower the amount of particles in direct contact with the interface. The multilayer arrangement was thus necessary to ensure efficient stabilization against coalescence, as it increased interface cohesiveness. We discussed the origin of this counterexample of the Finkle’s rule.

2011-28

Electric Field Induced Chemical Locomotion of Conducting Objects
mardi 15 novembre 2011
Loget G., Kuhn A.Nature Comm. 2011, 2, 535 Externally triggered motion of small objects shows a general promise in applications ranging from micromachines to drug delivery and self-assembly of... Read More...
Bipolar Electrochemistry : An Emerging Tool in Nanoscience
mercredi 9 novembre 2011
Loget G., Kuhn A.G.I.T. Laboratory Journal 2011, 5-6, 19-21. Bipolar electrochemistry is a concept with a quite long history, but has only very recently revealed its virtues in the field... Read More...
Distribution intramoléculaire de l’Acide alpha-linolénique dans les Triglycérides lymphatiques suite à l’Absorption de Triglycérides structurés chez le Rat
mardi 1 novembre 2011
Couedelo L., Vaysse C., Guy A., Gosse I., Durant T., Pinet S., Simon N., Cansell M., Combe N.Lipid Nutri+ 2011, 12 La dernière édition des apports nutritionnels conseillés pour la population... Read More...
Water-in-Oil Emulsions Stabilized by Water-Dispersible Poly(N-isopropylacrylamide) Microgels: Understanding Anti-Finkle Behavior
vendredi 21 octobre 2011
Destribats M., Lapeyre V., Sellier E., Leal-Calderon F., Schmitt V., Ravaine V.Langmuir 2011, 27(23), 14096-14107 Emulsions were prepared using poly(N-isopropylacrylamide) microgels as...
C3-triiodocyclotriveratrylene as Key Intermediate to Fluorescent Probes: Application to Selective Choline Recognition
mardi 27 septembre 2011
Peyrard L., Chierici S., Pinet S., Batat P., Jonusauskas G., Pinaud N., Meyrand P., Gosse I.Org. Biomol. Chem. 2011, 9, 8489-8494 A new strategy to obtain fluorescent cyclotriveratrylene (CTV)... Read More...
« Images de chimistes » : un Concours des jeunes Chimistes Aquitains pour un autre Regard sur notre Discipline
jeudi 15 septembre 2011
Loget G., Peyrard L., Ung V., Abadie T.L'Actualité Chimique 2011, 355, 50-51 La section Aquitaine de la Société Chimique de France inclut depuis janvier 2011 un club de jeunes chimistes qui a... Read More...
Multiscale-tailored Bioelectrode Surfaces for Optimized Catalytic Conversion Efficiency
mercredi 7 septembre 2011
Bon Saint-Côme Y., Lalo H., Wang Z., Etienne M., Gajdzik J., Kohring G-W., Walcarius A., Hempelmann R., Kuhn A.Langmuir 2011, 27, 12737-12744 We describe the elaboration of a multi-scale tailored... Read More...
Designed Glucose-responsive Microgels with Selective Shrinking Behavior
lundi 5 septembre 2011
Ancla C., Lapeyre V., Gosse I., Catargi B., Ravaine V.Langmuir 2011, 27, 12693-12701 We report on the synthesis of various glucose-responsive microgels based on N-alkylacrylamide derivatives and... Read More...
Miniaturisation, la Base des Capteurs de Demain
jeudi 1 septembre 2011
Sojic N., Kuhn A.Annales de la Société des Experts Chimistes de France 2011, 975, 35-41. Les capteurs sont devenus indispensables pour de nombreux aspects de notre vie avec des exemples... Read More...
Kinetic Investigations of the Electrochemical Bromination of Peracetylated D-glucal in Organic Solvents
mardi 30 août 2011
Segan D., Vukicevic R. D., Segan S., Sojic N., Buriez O., Manojlovic D.Electrochimica Acta 2011, 56, 9968-9972 Cyclic voltammetry and ultramicroelectrodes were used to investigate the kinetic... Read More...
Bipolare Elektrochemie : ein Werkzeug der Zukunft auf dem Gebiet der Nanowissenschaften
lundi 1 août 2011
Loget G., Kuhn A.GIT Laborfachzeitschrift 2011, 4, 236. Die bipolare Elektrochemie hat zwar schon einen ziemlich langen Werdegang hinter sich, ihre Vorteile auf dem Gebiet der Nanowissenschaft sind... Read More...
Electrochemically-assisted Deposition of Sol-gel Bio-composite with Co-immobilized Dehydrogenase and Diaphorase
samedi 23 juillet 2011
Wang Z., Etienne M., Kohring G-W., Bon Saint-Côme Y., Kuhn A., Walcarius A.Electrochim. Acta. 2011, 56, 9032 We report here that the electrochemically-assisted deposition (E-AD) of silica thin films... Read More...
Multifunctional Fe3O4 Nanoparticles for Targeted Bi-modal Imaging of Pancreatic Cancer
vendredi 22 juillet 2011
Olariu C. I., Yiu H. H. P., Bouffier L., Nedjadi T., Costello E., Williams S. R., Halloran C. M., Rosseinsky M. J.J. Mater. Chem. 2011, 21, 12650-12659 Amine and carboxylic acid-bifunctionalized iron... Read More...
Soft Microgels as Pickering Emulsion Stabilisers: Role of Particle Deformability
lundi 11 juillet 2011
Destribats M., Lapeyre V, Wolfs M., Sellier E., Leal-Calderon F., Ravaine V., Schmitt V.Soft Matter 2011, 7, 7689-7698  We synthesised soft uncharged microgels made of... Read More...
L'Electrochimie Bipolaire, un nouvel Outil pour la Chimie Analytique et les Nanosciences
dimanche 10 juillet 2011
Loget G., Kuhn A.Techniques de l'Ingénieur 2011, 7, RE208 L'électrochimie bipolaire est une technique relativement peu connue qui attire de plus en plus l'attention de la communauté scientifique.... Read More...
Photopatterning of Ultrathin Electrochemiluminescent Redox Hydrogel Films
vendredi 8 juillet 2011
Milutinovic M., Suraniti E., Studer V., Mano N., Manojlovic D., Sojic N.Chem. Comm. 2011, 47, 9125-9127 Photoinitiated polymerization is efficiently and rapidly carried out to immobilize ultrathin... Read More...
Glucose Sensing by Electrogenerated Chemiluminescence of Glucose-dehydrogenase Produced NADH on Electrodeposited Redox Hydrogel
mardi 14 juin 2011
Milutinovic M., Sallard S., Manojlovic D., Mano N., Sojic N.Bioelectrochemistry 2011, 82, 63-68 In this work, we report a new sensing approach based on electrogenerated chemiluminescence (ECL) in an... Read More...
Coupling Amperometry and Total Internal Reflection Fluorescence Microscopy at ITO surfaces for Monitoring Exocytosis of Single Vesicles
mercredi 27 avril 2011
Meunier A., Jouannot O., Fulcrand R., Fanget I., Bretou M., Karatekin E., Arbault S., Guille M., Darchen F., Lemaitre F., Amatore C. Angew. Chem. Int. Ed. 2011, 50(22), 5081-5084 A microdevice based... Read More...
Electrochemical Analysis of the Interactions and Reactivity of Ferrocene-based Drugs with a Lipid Environment: a Qualitative Overview
dimanche 24 avril 2011
Mertins O., Messina P., Labbé E., Arbault S., Lemaitre F., Buriez O., Amatore C. Inorganica Chimica Acta 2011, 374(1), 59-68 Transport, reactivity and interactions of anti-tumor ferrocene-based... Read More...
A Versatile Procedure for the Synthesis of Janus-type Carbon Tubes
jeudi 21 avril 2011
Loget G., Lapeyre V., Garrigue P., Warakulwit C., Limtrakul J., Delville M.-H., Kuhn A. Chem.Mater. 2011, 23, 2595-2599 A bulk procedure based on bipolar electrochemistry is proposed for the... Read More...
Chemical Grafting of a DNA Intercalator Probe onto Functional Iron Oxide Nanoparticles: A Physicochemical Study
mercredi 13 avril 2011
Bouffier L., Yiu H. H. P., Rosseinsky M. J.Langmuir 2011, 27, 6185-6192. Spherical magnetite nanoparticles (MNPs, 24 nm in diameter) were sequentially functionalized with... Read More...
Ordered Macroporous Ruthenium Oxide Electrodes for Potentiometric and Amperometric Sensing Applications
mardi 12 avril 2011
Lenz J., Trieu V., Hempelmann R., Kuhn A. Electroanalysis 2011, 23, 1186-1192. We report two methods to prepare ordered macroporous ruthenium oxide electrodes based on a template approach and their... Read More...
Large Conductance Changes in Peptide Single Molecule Junctions Controlled by pH
jeudi 31 mars 2011
Scullion L., Doneux T., Bouffier L., Fernig D. G., Higgins S. J., Bethell D., Nichols R. J.J. Phys. Chem. C 2011, 115, 8361-8368.Because electron transfer is often highly sensitive to bridge length... Read More...
Shaping and Exploring the Micro- and Nanoworld using Bipolar Electrochemistry
jeudi 31 mars 2011
Loget G., Kuhn A.Anal. Bioanal. Chem. 2011, 400, 1691-1704.Bipolar electrochemistry is a technique with a rather young history in the field of analytical chemistry. Being based on the polarization of... Read More...
Fast and Easy Enzyme Immobilization by Photoinitiated Polymerization for Efficient Bioelectrochemical Devices
mardi 15 mars 2011
Suraniti E., Studer V., Sojic N., Mano N.Anal. Chem. 2011, 83, 2824–2828 Immobilization and electrical wiring of enzymes is of particular importance for the elaboration of efficient biosensors and... Read More...
Synapses artificielles et Stress oxydant
mardi 1 février 2011
Amatore C., Arbault S., Guille M., Lemaitre F.Actualité Chimique 2011, 348-349, 25-31 La production de radicaux libres par les êtres vivants aérobiques a certainement une très mauvaise presse,... Read More...
Straightforward Single-step Generation of Microswimmers by Bipolar Electrochemistry
samedi 22 janvier 2011
Fattah Z., Loget G., Lapeyre V., Garrigue P., Warakulwit C., Limtrakul J., Bouffier L., Kuhn A. Electrochimica Acta 2011, 56, 10562-10566. Autonomous microswimmers are of enormous interest not only... Read More...
Macroporous Microelectrode Arrays for Measurements with Reduced Noise
mardi 11 janvier 2011
Urbanova V., Li Y., Vytras K., Yvert B., Kuhn A.J. Electroanal. Chem. 2011, 656(1-2), 91-95. In order to understand the dynamics of large neuronal networks, one of the challenges of nowadays... Read More...
Design of Catalytically Active Cylindrical and Macroporous Gold Microelectrodes
lundi 6 décembre 2010
Reculusa S., Heim M., Gao F., Mano N., Ravaine S., Kuhn A. Adv. Funct. Mater., 2011, 21, 691-698. Porous gold structures with a well-defined pore size and thickness are obtained through... Read More...
Electrogeneration of Ultra-thin Silica Films for the Functionalization of Macroporous Electrodes
vendredi 3 décembre 2010
Qu F., Nasraoui R., Etienne M., Bon Saint-Côme Y., Kuhn A., Lenz J., Gajdzik J., Hempelmann R., Walcarius A.Electrochem. Comm. 2011, 13, 138-142.Electro-assisted generation of ultra-thin silica... Read More...
Opto-Electrochemical Nanosensor Array for Remote DNA Detection
jeudi 14 octobre 2010
Deiss F., Laurent S., Descamps E., Livache T., Sojic N.Analyst 2011, 1336, 327-331A high-density array of opto-electrochemical nanosensors is presented for remote DNA detection. It was fabricated by... Read More...