A. Sauret, E. C. Barney, A. Perro, E. Villermaux, H. A. Stone and E. Dressaire 

Applied Physics Letters 2014, 105, 074101 

We report on a microfluidic method that allows measurement of a small concentration of largecontaminants in suspensions of solid micrometer-scale particles. To perform the measurement, we flowthe colloidalsuspension through a series of constrictions, i.e., a microchannel of varying cross-section. We show and quantify the role of large contaminants in the formation of clogs at a constriction and the growth of the resulting filter cake. By measuring the time interval between two clogging events in an array of parallel microchannels, we are able to estimate the concentration of contaminants whose size is selected by the geometry of the microfluidic device. This technique for characterizing colloidalsuspensions offers a versatile and rapid tool to explore the role of contaminants on the properties of thesuspensions.

 

D. Tarus, E. Hachet, L. Messager, B. Catargi, V. Ravaine, R. Auzély-Velty

Macromol. Rapid. Commun. 2014, 35, 2089 -2095

Dynamic covalent hydrogels are facilely prepared from biocompatible polysaccharides in physiological conditions by the formation of phenylboronate ester cross-links. This is based on the simple mixing of carboxylate-containing polysaccharides (i.e., hyaluronic acid or carboxymethylcellulose) modified with phenylboronic acid and maltose moieties according to mild coupling reactions performed in aqueous solution. The formation of dynamic networks based on reversible boronic-ester cross-links is demonstrated by analyzing their rheological behavior. This study shows that these gels can adapt their structure in response to chemical stimuli such as variations in pH or addition of glucose and self-heal.

2015-3

 

 

H. Sopha, J. Roche, I. Švancara, A. Kuhn

Anal.Chem. 2014, 86, 10515–10519

In this contribution, a wireless method for the electrolytic sampling of heavy metals at special bismuth-modified particles is presented. For the first time, glassy carbon beads were asymmetrically modified with bismuth using bipolar electrochemistry. The resulting chemically asymmetric beads, so-called Janus particles, could be employed for the wireless electroaccumulation of heavy metal ions in the bismuth film. The qualitative and quantitative aspects of this concept have been studied by using anodic stripping voltammetry with Cd2+ and Pb2+ as the model ions. Different experimental and instrumental parameters have been optimized, among others the concentration of Bi3+ ions, the deposition conditions for the bismuth-film, and the accumulation time of the target heavy metals.The developed concept could be applied to the transfer of heavy metal ions from a solution into a confined space without need to electrically connect the collector (electrode), thus representing an interesting new approach for trace metal analysis in small volumes.2014-22

P. Masse, E. Sellier, V. Schmitt, and V. Ravaine

Langmuir, 2014, 30 (49), pp 14745–14756

The importance of electrostatics on microgel adsorption at a liquid interface is studied, as well as its consequence on emulsion stabilization. In this work, poly(N-isopropylacrylamide) (pNIPAM) microgels bearing different numbers of charges and various distribution profiles are studied, both in solution and at the oil–water interface of emulsion drops. Charged microgels are compared to neutral ones, and electrostatic interactions are screened by adding salt to the aqueous solution. In solution, electrostatics has a significant impact on microgel swelling, as induced by the osmotic pressure exerted by mobile counterions in the gel network. At the interface of drops, microgels pack in a hexagonal array, whose lattice parameter is independent of the number of charges and range of electrostatic interactions. Microgel morphology and packing are ruled only by the adsorption of the pNIPAM chain at the interface. Conversely, decreasing the charge density of microgels by the protonation of the carboxylic groups leads to unstable emulsions, possibly as a result of the impact of hydrogen bonding on microgel deformability.

2015-2

J. Roche, S. Carrara, J. Sanchez, J. Lannelongue, G. Loget, L. Bouffier, P. Fischer, A. Kuhn
Sci. Rep. 2014, 4, 6705

Miniaturized structures that can move in a controlled way in solution and integrate various functionalities are attracting considerable attention due to the potential applications in fields ranging from autonomous micromotors to roving sensors. Here we introduce a concept which allows, depending on their specific design, the controlled directional motion of objects in water, combined with electronic functionalities such as the emission of light, sensing, signal conversion, treatment and transmission. The approach is based on electric field-induced polarization, which triggers different chemical reactions at the surface of the object and thereby its propulsion. This results in a localized electric current that can power in a wireless way electronic devices in water, leading to a new class of electronic swimmers (e-swimmers).

2014-21

Thumbnail S. Assavapanumat, T. Yutthalekha, P. Garrigue, B. Goudeau, V. Lapeyre, A. Perro, N. Sojic, C. Wattanakit, A. Kuhn Angew. Chem. Int. Ed. 58 (2019) 3471 (Back Cover) see also CNRS press release...
Thumbnail S. Voci, B. Goudeau, G. Valenti, A. Lesch, M. Jović, S. Rapino, F. Paolucci, S. Arbault, N. Sojic J. Am. Chem. Soc., 140,2018, 14753-14760 Herein is reported a surface-confined microscopy based...
Thumbnail Hanan Al-Kutubi, Silvia Voci, Liza Rassaei, Neso Sojic, Klaus Mathwig Chem .Sci., 9, 2018, (2018 Chemical Science HOT Article Collection) Microfabricated nanofluidic electrochemical devices offer a...
Thumbnail L. Bouffier, S. Arbault, A. Kuhn, N. Sojic Techniques de l’Ingénieur. 2018. P156 Les mesures sélectives et sensibles dans des échantillons complexes tels que l’urine ou le sang sont devenues des outils...
Thumbnail H. Labie, A. Perro, V. Lapeyre, B. Goudeau, B. Catargi, R. Auzély, V. Ravaine Journal of Colloid and Interface Science 535 (2019) 16–27 A simple route to deliver on demand hydrosoluble molecules such...
Thumbnail E.Krisch, B. Gyarmati, D. Barczikai, V. Lapeyre, B.A. Szilágyi, V. Ravaine, A. Szilágyi European Polymer Journal 105 (2018) 459–468 Redox and pH responsive hydrogels were synthesized, which can...
Thumbnail L. Zhang, B. Gupta, B. Goudeau, N. Mano, A. Kuhn J. Am. Chem. Soc 140 (2018) 15501 Collecting electrochemical information concerning the presence of molecules in a solution is usually achieved by measuring...
Thumbnail L. Adam, A. Kuhn Techniques de l'Ingénieur (2019)Ref:IN189 V1 Les molécules chirales sont d’un grand intérêt dans un certain nombre de domaines tels que la médecine, la biologie ou encore la chimie....
Thumbnail J.-P. Douliez, A. Perro, J.-P. Chapel, B. Goudeau and L. Béven Small 2018, 1803042 A template-free all-aqueous bulk preparation of robust hollow capsules having a gelatin shell from all-in-water...
Thumbnail G. Salinas, B. A. Frontana-Uribe, S. Reculusa, P. Garrigue, A. Kuhn Anal.Chem. 90 (2018) 11770 Highly ordered macroporous electrodes of the conducting polymer poly-3,4-ortho-xylendioxythiophene...
Thumbnail T. D. Le, L. Zhang, S. Reculusa, G.Vignoles, N. Mano, A. Kuhn, D. Lasseux ChemElectroChem 6 (2018) 173 This article reports on a procedure to predict the optimal thickness of cylindrical porous...
Thumbnail A. de Poulpiquet, B. Goudeau, P. Garrigue, N. Sojic, S. Arbault, T. Doneux, L. Bouffier. Chem. Sci. 2018, 9, 6622-6628. The coupling between electrochemistry and fluorescence confocal laser scanning...
Thumbnail V. Pirenne, G. Kurtay, S. Voci, L. Bouffier, N. Sojic, F. Robert, D. M. Bassani, Y. Landais. Org. Lett. 2018, 20 (15), 4521-4525. Eosin-Y (EY)-mediated alkylsulfonyl cyanation of olefins was shown...
Thumbnail I. Hernández Delgado, S. Pascal, C. Besnard, S. Voci, L. Bouffier, N. Sojic, J. Lacour. Chem. Eur. J. 2018, 24 (40), 10186-10195. A series of nine C‐functionalized cationic diazaoxa triangulene...
Thumbnail E. Suraniti, P. Merzeau, J. Roche, S. Gounel, A. G. Mark, P. Fischer, N. Mano, A. Kuhn Nature Comm. 2018, 9:3229 see also CNRS press release Chemical systems do not allow the coupling of energy from...
Thumbnail D. Kos, H. P. A. G. Astier, G. D. Martino, J. Mertens, H. Ohadi, D. De. Fazio, D. Yoon, Z. Zhao, A. Kuhn, A. C. Ferrari, C. J. B. Ford, J. J. Baumberg Small 14 (2018) 1801599 Nanoactuators are a key...
Thumbnail Ruigrok, H.J., Arnaud-Cormos D., Hurtier A., Poque-Haro E., Poulletier de Gannes F., Ruffié G., Bonnaudin F, Lagroye I., Sojic N., Arbault S., Lévêque P., Veyret B. and Percherancier Y. Radiation...
Thumbnail Girard F., Peret M., Dumont N., Badets V., Blanc S., Gazeli K., Noël C., Belmonte T., Marlin L., Cambus J.P., Simon G., Sojic N., Held B., Clément F. and Arbault S. Phys. Chem. Chem. Phys., 2018, 20,...
Thumbnail Lefrançois P., Goudeau B., Arbault S. Integrative Biology, 2018, in press Phospholipid Giant Unilamellar Vesicles (GUVs) are usually prepared by electroformation in water, that is in a...
Thumbnail E. Suraniti, A.G. Mark, J. Roche, H. Richter, A. Kuhn, P. Fischer, N. Mano L’Actualité Chimique 2018, 427-428,127-128 Une micro-source d’énergie intégrée permettrait à des implants biomédicaux...