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 Dezest M., Bulteau A.L., Quinton D., Chavatte L., Le Béchec M., Arbault S., Salvayre A.N., Cousty S., Clément F. PLOS One, 2017, 12(3) Cold atmospheric pressure plasmas (CAPPs) are known to have...
Thumbnail C. Wattanakit, T. Yutthalekha, S. Asssavapanumat, V. Lapeyre, A. Kuhn Nature Comm. 2017, 8, 2087 see also CNRS press release Asymmetric synthesis of molecules is of crucial importance to obtain...
Thumbnail Giovanni Valenti, Sabina Scarabino, Bertrand Goudeau, Andreas Lesch, Milica Jovic, Elena Villani, Milica Sentic, Stefania Rapino, Stephane Arbault, Francesco Paolucci, and Neso Sojic J. Am. Chem....
Thumbnail V. Eßmann, S. Voci, G. Loget, N. Sojic, W. Schuhmann, A. Kuhn J. Phys. Chem. Lett. 2017,8, 4930–4934   Bipolar electrochemistry has been shown to enable and control various kinds of propulsion of...
Thumbnail Guangnan Meng, Vinothan N. Manoharan and Adeline Perro Soft Matter, 2017,13, 6293-6296 We design polystyrene–poly(N′-isopropylacrylamide-co-acrylic acid) core–shell particles that exhibit...
Thumbnail J. Gao, S. Chen, F. AlTal, S. Hu, L. Bouffier, G. Wantz.  ACS Appl. Mater. Interfaces, 2017, 9, 32405–32410.  A linear array of aluminum discs is deposited between the driving electrodes of an...
Thumbnail B. Gupta, B. Goudeau, A. Kuhn Angew.Chem. Int. Ed. 2017, 56, 14183-14186 see also Highlight in Chemistry Views and CNRS press release Electrochemical actuation of conducting polymers usually...
Thumbnail Z. Ali Fattah, L. Bouffier, A. Kuhn Applied Materials Today 2017, 9, 259–265, COVER Self-propelled micro/nanoswimmers performing directional motion are of great potential nowadays in the frame of...
Thumbnail T.D. Le, D. Lasseux, X.P. Nguyen, G. Vignoles, N. Mano, A. Kuhn Chemical Engineering Science 2017, 173, 153–167 A multi-scale model of diffusion/reaction at play in a porous electrode is developed...
Thumbnail M. Dabrowski, M. Cieplak, K. Noworyta, M. Heim, W. Adamkiewicz, A. Kuhn, P. S. Sharma, W. Kutner J. Mater. Chem. B, 2017,5, 6292-6299 Molecular imprinting in polymers leads, among others, to...
Thumbnail L. Bouffier, T. Doneux.  Current Opinion in Electrochemistry, DOI: 10.1016/j.coelec.2017.06.015. Electrochemistry and fluorescence microscopy are two complementary transduction techniques that offer synergetic...
Thumbnail G. Di Martino,V. A. Turek,  A. Lombardi, I.  Szabó, B. de Nijs,  A. Kuhn, E. Rosta, J.J. Baumberg Nano Lett. 2017, 17, 4840-4845 We study in real time the optical response of individual plasmonic...
Thumbnail Rémy Bois, Sabina Scarabino, Valérie Ravaine, Neso Sojic Langmuir, 2017, DOI: 10.1021/acs.langmuir.7b01585 We describe a method to confine electrochemiluminescence (ECL) at the oil-water interface of emulsion...
Thumbnail D. Zigah, O. Fontaine World Scientific, 2017, ISBN: 978-1-78634-353-6   Bioelectrochemical Systems (BESs) are innovative and sustainable devices. They combine biological and electrochemical...
Thumbnail C. Bodin,  E. Mourad,  D. Zigah,  S. Le Vot,  S. A Freunberger,  F. Favier, O. Fontaine Faraday Discuss., 2017,DOI: 10.1039/C7FD00174F   Nowadays, commercial supercapacitors are based on purely...
Thumbnail S. Tiewcharoen, C. Warakulwit, V. Lapeyre, P. Garrigue, L. Fourier, C. Elissalde, S. Buffière, P. Legros, M. Gayot, J. Limtrakul, A. Kuhn Angew.Chem.Int.Ed. (2017) 56, 11431-11435, COVER, HOT...
Thumbnail G. Di Martino, V. A. Turek,  C. Tserkezis, A. Lombardi, A. Kuhn, J.J. Baumberg Faraday Discuss., 2017, in press,doi 10.1039/C7FD00130D We study the optical response of individual nm-wide plasmonic...
Thumbnail A. G. Mark, E. Suraniti, J. Roche, H. Richter, A. Kuhn, N. Mano, P. Fischer Lab Chip, 2017, 17, 1761 HOT PAPER see also CNRS press release A variety of diagnostic and therapeutic medical...
Thumbnail I. Malytska, C. Mézière, M. Keilar, L. Hirsch, G. Wantz, N. Avarvari, A. Kuhn, L. Bouffier. Journal of Physical Chemistry C 2017, 121, 12921-12927.   Bipolar electrochemistry has recently emerged as a very...
Thumbnail L. Bouffier, S. Reculusa, V. Ravaine, A. Kuhn. ChemPhysChem 2017, 18, 2637-2642.   A new simple and versatile method for the preparation of surface wetting gradients is proposed. It is based on the...
Thumbnail C.A. Busatto, H. Labie, V. Lapeyre, R. Auzely-Velty, A. Perro, N. Casis, J. Luna, D.A. Estenoz, V. Ravaine Journal of Colloid and Interface Science, 493, 2017, 356–364. Polymer microgels have received...
Thumbnail L. Bouffier, N. Sojic, A. Kuhn Electrophoresis, 2017, 38, 2687-2694. A bipolar electrode is quite unconventional as it behaves simultaneously as an anode and a cathode in contrast to a classic...
Thumbnail M. Dabrowski, M. Cieplaka, P. Sindhu Sharma, P. Borowicz, K. Noworyta, W. Lisowski, F. D'Souza, A. Kuhn, W. Kutner Biosens.&Bioelectron.2017, 94, 155-161 Nanostructured artificial receptor...
Thumbnail Nenad R. Filipovic, Hana Elshaflu, Sonja Grubic, Ljiljana S. Jovanovic, Marko Rodic, Irena Novakovic, Aleksandar Malecevic, Ivana S. Djordjevic, Haidong Li, Neso Sojic, Aleksandar Marinkovic,...
Thumbnail Haidong Li, Silvia Voci, Antoine Wallabregue, Catherine Adam, Geraldine M. Labrador, Romain Duwald, Irene Hernández Delgado, Simon Pascal, Johann Bosson, Jérôme Lacour, Laurent BouffierNeso...