Search

Your search keyword '"Demoustier-Champagne S"' showing total 128 results
Start Over Author "Demoustier-Champagne S"
128 results on '"Demoustier-Champagne S"'

1. Structural and electrical characterization of hybrid metal-polypyrrole nanowires

Author

Gence, L., Faniel, S., Gustin, C., Melinte, S., Bayot, V., Callegari, V., Reynes, O., and Demoustier-Champagne, S.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

We present here the synthesis and structural characterization of hybrid Au-polypyrrole-Au and Pt- polypyrrole-Au nanowires together with a study of their electrical properties from room-temperature down to very low temperature. A careful characterization of the metal-polymer interfaces by trans- mission electron microscopy revealed that the structure and mechanical strength of bottom and upper interfaces are very different. Variable temperature electrical transport measurements were performed on both multiple nanowires - contained within the polycarbonate template - and single nanowires. Our data show that the three-dimensional Mott variable-range-hopping model provides a complete framework for the understanding of transport in PPy nanowires, including non-linear current-voltage characteristics and magnetotransport at low temperatures., Comment: Phys. Rev. B Vol. 76 Issue 11 (2007)

Published
2011
Full Text
View/download PDF

2. Mechanical properties of nanotubes of polyelectrolyte multilayers

Author

Cuenot, S. Stéphane, Alem, H., Louarn, G., Demoustier-Champagne, S., and Jonas, A. M.

Subjects
Condensed Matter - Materials Science
Abstract

The elastic properties of nanotubes fabricated by layer-by-layer (LbL) assembly of polyelectrolytes in the nanopores of polycarbonate track-etched membranes have been investigated by resonant contact Atomic Force Microscopy (AFM), for nanotube diameters in the range of 100 to 200 nm. The elastic modulus of the nanotubes was computed from the resonance frequencies of a cantilever resting on freely suspended LbL nanotubes. An average value of 115MPa was found in air for Young's modulus of these nanostructures, well below the values reported for dry, flat multilayers, but in the range of values reported for water-swollen flat multilayers. These low values are most probably due to the lower degree of ionic cross-linking of LbL nanotubes and their consequently higher water content in air, resulting from the peculiar mode of growth of nanoconfined polyelectrolyte multilayers.

Published
2009
Full Text
View/download PDF

14. Physical properties of magnetic metallic nanowires and conjugated polymer nanowires and nanotubes

Author

Duvail, J-L., Dubois, S., Demoustier-Champagne, S., Long, Y., and Piraux, L.

Subjects
Nanotechnology -- Magnetic properties, High technology industry
Abstract

Byline: J-L. Duvail, S. Dubois, S. Demoustier-Champagne, Y. Long, L. Piraux The unique physical properties of nanowires and nanotubes originate from either the small dimensions of the objects, or structural modifications induced by the confined synthesis and surface effects. These features make them very promising for applications in nanoelectronics and nanosensors in particular. In this paper, we review our results on magnetic metallic nanowires and conjugated polymer nanowires and nanotubes prepared by the template method. Their magnetic, electrical and optical properties differ from the bulk counterparts. Mechanisms responsible for these differences have been identified.

Published
2008

15. Osteogenetic properties of electrospun nanofibrous PCL scaffolds equipped with chitosan-based nanoreservoirs of growth factors

Author

Ferrand, A., Eap, S., Laura Richert, Lemoine, S., Kalaskar, D., Demoustier-Champagne, S., Atmani, H., Mely, Y., Fioretti, F., Guy Schlatter, Kuhn, L., Ladam, G., Benkirane-Jessel, N., Barthel, Ingrid, Immuno-Rhumatologie Moléculaire, Institut National de la Santé et de la Recherche Médicale (INSERM)-Université de Strasbourg (UNISTRA), Université Henri Poincaré - Nancy 1 (UHP), Institut de la matière condensée et des nanosciences / Institute of Condensed Matter and Nanosciences (IMCN), Université Catholique de Louvain = Catholic University of Louvain (UCL), Micro-Environnement et Régulation Cellulaire Intégrée (MERCI), Université de Rouen Normandie (UNIROUEN), Normandie Université (NU)-Normandie Université (NU), Laboratoire de Biophotonique et Pharmacologie - UMR 7213 (LBP), Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA)), Biomatériaux et ingénierie tissulaire, Université Louis Pasteur - Strasbourg I-Institut National de la Santé et de la Recherche Médicale (INSERM), Laboratoire d'Ingenierie des Polymères pour les Hautes Technologies, and Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS)

Subjects
[SDV] Life Sciences [q-bio], [CHIM.POLY]Chemical Sciences/Polymers, [CHIM.THER]Chemical Sciences/Medicinal Chemistry, [SDV.IB.BIO]Life Sciences [q-bio]/Bioengineering/Biomaterials, ComputingMilieux_MISCELLANEOUS
Abstract

International audience; Bioactive implants intended for rapid, robust, and durable bone tissue regeneration are presented. The implants are based on nanofibrous 3D-scaffolds of bioresorbable poly-e-caprolactone mimicking the fibrillar architecture of bone matrix. Layer-by-layer nano-immobilization of the growth factor BMP-2 in association with chitosan (CHI) or poly-L-lysine over the nanofibers is described. The osteogenetic potential of the scaffolds coated with layers of CHI and BMP-2 is demonstrated in vitro, and in vivo in mouse calvaria, through enhanced osteopontin gene expression and calcium phosphate biomineralization. The therapeutic strategy described here contributes to the field of regenerative medicine, as it proposes a route toward efficient repair of bone defects at reduced risk and cost level.

Published
2014
Full Text
View/download PDF

17. Factors impacting protein adsorption on layer-by-layer assembled stimuli-responsive thin films.

Author

Fustin, C.-A., Demoustier-Champagne, S., Osypova, A., Pradier, C.-M., and Landoulsi, J.

Subjects
*PROTEIN synthesis, *ADSORPTION (Chemistry), *STIMULUS & response (Biology), *POLYELECTROLYTES, *BLOCK copolymers
Abstract

Studying the stimuli-response of polyelectrolyte multilayers (PEMs) towards protein adsorption requires coping with the multiplicity of factors influencing interfacial processes. In this study, we report the design of a nanostructured stimuli-responsive coating based on the sequential layer-by-layer assembly of poly(N-isopropylacrylamide) block copolymers with poly (allylamine hydrochloride) and scrutinize its ability to modulate protein adsorption. The results reveal that the stimuli-response of the film towards protein adsorption under T, pH and I changes is strongly influenced by the type of buffer. This latter parameter has indeed a significant impact on the adsorbed amount of proteins, while it has only slight effect on the stimuli-response of free block copolymer, on the mechanism of PEM growth and the properties of the obtained film. In conditions favorable to protein adsorption, the use of anionic buffer leads to the adsorption of an apparent monolayer of proteins, while in zwitterionic buffer, proteins adsorb in a significantly higher amount. This trend may be explained by a more efficient charge screening of macromolecules by zwitterions which reduce the repulsion between proteins, leading to their accumulation at the interface. Finally, the length of the poly(N-isopropylacrylamide) block is shown to be another key factor impacting the amount of adsorbed proteins. The findings reported in this paper provide relevant information and allow the evaluation of stimuli-response of PEM to be carried out under optimized conditions. [ABSTRACT FROM AUTHOR]

Published
2017
Full Text
View/download PDF

21. High current density nanofilament cathodes for microwave amplifiers

Author

Schnell, J-P., Schnell, J-P., Minoux, E., Gangloff, L., Vincent, P., Legagneux, P., Dieumegard, D., David, J.-F., Peauger, F., Hudanski, L., Teo, K.B.K., Lacerda, R., Chhowalla, M., Hasko, D.G., Ahmed, H., Amaratunga, G.A.J., Milne, W.I., Vila, L., Dauginet-De Pra, L., Demoustier-Champagne, S., Ferain, E., Legras, R., Piraux, L., Gröening, O., Raedt, H. De, Michielsen, K., Schnell, J-P., Schnell, J-P., Minoux, E., Gangloff, L., Vincent, P., Legagneux, P., Dieumegard, D., David, J.-F., Peauger, F., Hudanski, L., Teo, K.B.K., Lacerda, R., Chhowalla, M., Hasko, D.G., Ahmed, H., Amaratunga, G.A.J., Milne, W.I., Vila, L., Dauginet-De Pra, L., Demoustier-Champagne, S., Ferain, E., Legras, R., Piraux, L., Gröening, O., Raedt, H. De, and Michielsen, K.

Abstract

We study high current density nanofilament cathodes for microwave amplifiers. Two different types of aligned nanofilament array have been studied: first, metallic nanowires grown by electrodeposition into nanoporous templates at very low temperature (T

Published
2004

29. Physical properties of conducting polymer nanofibers

Author

Duvail, J.L., primary, Rétho, P., additional, Godon, C., additional, Marhic, C., additional, Louarn, G., additional, Chauvet, O., additional, Cuenot, S., additional, Nysten, B., additional, Dauginet-De Pra, L., additional, and Demoustier-Champagne, S., additional

Published
2003
Full Text
View/download PDF

33. Quartz Crystal Microbalance Study of Ionic Strengthand pH-Dependent Polymer Conformation and Protein Adsorption/Desorptionon PAA, PEO, and Mixed PEO/PAABrushes.

Author

Delcroix, M. F., Demoustier-Champagne, S., and Dupont-Gillain, C. C.

Subjects
*QUARTZ crystal microbalances, *IONIC strength, *HYDROGEN-ion concentration, *POLYMERS, *ETHYLENE oxide, *ADSORPTION (Chemistry), *POLYACRYLIC acid
Abstract

The conformation of polymer chains grafted on a substrate influencesprotein adsorption. In a previous study, adsorption/desorption ofalbumin was demonstrated on mixed poly(ethylene oxide) (PEO)/poly(acrylicacid) (PAA) brushes, triggered by solutions of adequate pH and ionicstrength (I). In the present work, homolayers ofPEO or PAA are submitted to saline solutions with pH from 3 to 9 and Ifrom 10–5to 10–1M,and their conformation is evaluated in real time using quartz crystalmicrobalance with dissipation monitoring (QCM-D). Shrinkage/swellingof PAA chains and hydration and salt condensation in the brush areevidenced. The adsorption of human serum albumin (HSA) onto such brushesis also monitored in these different saline solutions, leading toa deep understanding of the influence of polymer chain conformation,modulated by pH and I, on protein adsorption. A detailedmodel of the conformation of PEO/PAA mixed brushes depending on pHand Iis then proposed, providing a rationale forthe identification of conditions for the successive adsorption anddesorption of proteins on such mixed brushes. The adsorption/desorptionof albumin on PEO/PAA is demonstrated using QCM-D [ABSTRACT FROM AUTHOR]

Published
2014
Full Text
View/download PDF

42. Surface Initiated Polymerization of Styrene from a Carboxylic Acid Functionalized Polypyrrole Coated Electrode

Author

Roux, S., Duwez, A.-S., and Demoustier-Champagne, S.

Abstract

Surface initiated radical polymerization (SIRP) is an elegant and efficient method to produce polymer chains attached to surfaces with a high graft density. Growth of polymer chains from a gold surface requires the formation of a self-assembled monolayer (SAM) of thiols functionalized by reactive groups (alcohol or carboxylic acid) in order to covalently bind free radical initiator species. However, thiol desorption induced by the temperature imposed for polymerization impedes the growth of polymer chains. We propose therefore to coat a gold electrode with a polypyrrole (PPy) derivative containing carboxylic acid pendant groups. The resulting conducting polymer layer was shown to be strongly attached to the surface. Grafting of the initiator (azo compound) and SIRP of styrene were successfully performed on this organic layer, as demonstrated by X-ray photoelectron spectroscopy (XPS), time-of-flight secondary ion mass spectrometry (TOF SIMS), and contact angle measurements. The roughness, the morphology, and the surface uniformity of the films were investigated by atomic force microscopy (AFM). Finally, cyclic voltammetry experiments were carried out to study the influence of the polystyrene layer on the electrochemical behavior of the conducting polymer.

Published
2003

44. Effect of Electrolyte Concentration and Nature on the Morphology and the Electrical Properties of Electropolymerized Polypyrrole Nanotubules

Author

Demoustier-Champagne, S. and Stavaux, P.-Y.

Abstract

Polypyrrole (PPy) with four different counterions was electrochemically synthesized in homemade polycarbonate particle track-etched membranes with different pore sizes. A dependence of the PPy growing rate on the pore size and on the electrolyte nature and concentration has been observed. The morphology of the different template-synthesized nanostructures has been carefully analyzed by field-emission scanning electron microscopy. In all cases, nanotubules were observed. However, their thickness depends on the pore diameter of the template membrane and on the nature of the supporting electrolyte. The electrical conductivity of PPy in such a structure is known to increase compared to the bulk conductivity, which is also shown here. In addition Raman spectroscopy showed that the relative conjugation length increases with decreasing pore size.

Published
1999

45. Coupling of α,ω-dichloropoly(methylphenylsilane) and living poly(styryllithium). Study of the coupling reaction

Author

Demoustier-Champagne, S., Canivet, I., Devaux, J., and Jerome, R.

Abstract

Both di- and triblock copolymers consisting of polystyrene (PS) in conjunction with poly(methylphenylsilane) (PMPS) have been successfully prepared by coupling of α,ω-dichloro-PMPS with poly(styryllithium). The study of this reaction has shown a sudden limitation of the coupling yield, which however depends on the PS block length. Both the polymer concentration and the solvent have also an effect on the coupling reaction. Morphology of the PS-PMPS block copolymers has been observed by transmission electron microscopy. Very complex morphologies have been reported more likely as the result of the competition between the phase separation induced by PS and PMPS immiscibility and the tendency of PMPS to form ordered structures. © 1997 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 35: 1939–1948, 1997

Published
1997
Full Text
View/download PDF

50. High current density nanofilament cathodes for microwave amplifiers

Author

Schnell, J.-P., primary, Minoux, E., additional, Gangloff, L., additional, Vincent, P., additional, Legagneux, P., additional, Dieurnegard, D., additional, David, J.-F., additional, Peauger, F., additional, Hudanski, L., additional, Teo, K.B.K., additional, Lacerda, R., additional, Chhowalla, M., additional, Hasko, D.G., additional, Ahmed, H., additional, Amaratunga, G.A.J., additional, Milne, W.I., additional, Vila, L., additional, Dauginet-De Pra, L., additional, Demoustier-Champagne, S., additional, Ferain, E., additional, Legras, R., additional, Piraux, L., additional, Groening, O., additional, De Raedt, H., additional, and Michielsen, K., additional

Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results