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

Thumbnail Loget G., Kuhn A.Nature Comm. 20112, 535 Externally triggered motion of small objects shows a general promise in applications ranging from micromachines to drug delivery and self-assembly of...
Thumbnail Loget G., Kuhn A.G.I.T. Laboratory Journal 20115-6, 19-21. Bipolar electrochemistry is a concept with a quite long history, but has only very recently revealed its virtues in the field...
Thumbnail 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...
Thumbnail 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...
Thumbnail 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) probes...
Thumbnail 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...
Thumbnail 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...
Thumbnail 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...
Thumbnail Sojic N., Kuhn A.Annales de la Société des Experts Chimistes de France 2011975, 35-41. Les capteurs sont devenus indispensables pour de nombreux aspects de notre vie avec des exemples...
Thumbnail Segan D., Vukicevic R. D., Segan S., Sojic N., Buriez O., Manojlovic D.Electrochimica Acta 201156, 9968-9972 Cyclic voltammetry and ultramicroelectrodes were used to investigate the kinetic...
Thumbnail Loget G., Kuhn A.GIT Laborfachzeitschrift2011, 4, 236. Die bipolare Elektrochemie hat zwar schon einen ziemlich langen Werdegang hinter sich, ihre Vorteile auf dem Gebiet der Nanowissenschaft...
Thumbnail 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...
Thumbnail 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...
Thumbnail 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...
Thumbnail Loget G., Kuhn A.Techniques de l'Ingénieur2011, 7,RE208 L'électrochimie bipolaire est une technique relativement peu connue qui attire de plus en plus l'attention de la communauté scientifique....
Thumbnail 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...
Thumbnail Milutinovic M., Sallard S., Manojlovic D., Mano N., Sojic N.Bioelectrochemistry2011, 82, 63-68 In this work, we report a new sensing approach based on electrogenerated chemiluminescence (ECL) in an...
Thumbnail 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...
Thumbnail 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...
Thumbnail 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...
Thumbnail 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...
Thumbnail Lenz J., Trieu V., Hempelmann R., Kuhn A. Electroanalysis2011, 23, 1186-1192. We report two methods to prepare ordered macroporous ruthenium oxide electrodes based on a template approach and their...
Thumbnail Scullion L., Doneux T., Bouffier L., Fernig D. G., Higgins S. J., Bethell D., Nichols R. J.J. Phys. Chem. C2011, 115, 8361-8368.Because electron transfer is often highly sensitive to bridge...
Thumbnail 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...
Thumbnail 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...
Thumbnail 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,...
Thumbnail Fattah Z., Loget G., Lapeyre V., Garrigue P., Warakulwit C., Limtrakul J., Bouffier L., Kuhn A. Electrochimica Acta2011, 56, 10562-10566. Autonomous microswimmers are of enormous interest not...
Thumbnail 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...
Thumbnail 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...
Thumbnail 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 films...