Le laboratoire « Matière et Systèmes Complexes » (MSC) est une unité mixte de recherche du CNRS et de l’université (UMR 7057). Le laboratoire est installé depuis 2007 sur le nouveau campus de l’Université Paris Diderot, Paris Rive Gauche, dans le bâtiment Condorcet. Il est réparti sur plusieurs étages. La direction et le secrétariat se trouvent au 6e étage. Le directeur actuel en est Laurent Limat, secondé par la directrice adjointe Florence Gazeau.
Le laboratoire MSC a pour sujet d’étude la matière et les systèmes complexes sous toutes leurs formes. Il peut s’agir de fluides montrant des phénomènes complexes non-linéaires (facettages de jets ou de tourbillons, structures et propriétés complexes de mousses, phénomènes de mouillage, propagation de vagues et de tsunamis) ou bien, par exemple, de systèmes proches de la géophysique et de l’environnement (systèmes granulaires tels que les dunes, phénomènes d’érosion, morphogenèse des plantes et même des villes, nage collective d’algues ou de bactéries…). Les études théoriques et expérimentales conduisent à des applications comme par exemple les éoliennes flexibles de haut rendement, l’optimisation de méthodes d’enduisage, le contôle de propriétés de surface ou la récupération de la biomasse (ingénierie verte)...
Le laboratoire étudie également le couplage entre la physique et la biologie des systèmes vivants, avec une approche multi-échelle. Les recherches effectuées vont d’échelles moléculaires ou supra-moléculaires (assemblages des protéines, chromatine, cytosquelette etc.) jusqu’à l’échelle de l’organisme entier (méduses, poulets, vers etc.) en passant par des études plus fondamentales sur des cellules uniques sur lesquelles sont exercées des forces quantifiées, permettant de comprendre les propriétés biophysiques de la matière vivante. Ces études aboutissent à de possibles applications en ingénierie tissulaire ou régénération des tissus avec des transferts dans le domaine médical.
Le laboratoire est structuré en cinq équipes :
Cependant les activités de ces équipes se recoupent souvent dans des projets communs aux frontières entre les comportements physiques et/ou biologiques (exemple : comportement de mousses marines, mesures de forces dans des tissus reconstitués, etc.)
Date: 7 Nov 2019 - 16:25
Desc: A simple method for elaborating mesoporous thin films with patterns normal to the substrate has been studied. The structured thin films were prepared by deposition of thin silica film templated by the so-called P123 (EO)20-(PO)69-(EO)20 (poly-[ethyleneoxide-co-propyleneoxide-co-ethyleneoxide]) triblock copolymer on monolayers of n-octadecyltrichlorosilane (OTS) assembled onto a silicon wafer. Surface morphologies of films deposited onto silicon wafers modified by this hydrophobic monolayer or cleaned hydrophilic bare silicon wafer were characterized by using atomic force microscopy (AFM). We evidenced that, in the case of hydrophobic modified substrate, organic–inorganic hybrid thin films made of P123 species embedded in a silica matrix exhibit regularly-shaped craters in the direction normal to the surface. Our investigation has shown that the diameter of the craters agrees fairly well with the length of the fully extended organic chains of the triblock copolymer. The specific interfacial interactions between both the hydrophilic part of the shell of the surfactant, the native silicon oxide of the silicon wafer and the silanized surface are discussed.
Date: 21 Dec 2021 - 11:51
Desc: This work discusses the influence of different metal hydride storage bed configurations. The objective was to design and optimize a solid-state hydrogen storage for a nonpolluting mobility. A study of the absorption and desorption dynamics of a loose powder bed was performed first, followed by three different storage bed configurations: compacted Ti-Mn alloy powder, alternated Ti-Mn alloy compacts with stainless steel fins and compacted [Ti-Mn alloy/Stainless steel] powder mixture. A numerical model was developed to simulate the heat transfer and the hydrogen absorption and desorption rates. The alternation and compact mixture configurations gave better heat transfer efficiencies, absorption and desorption rates and increased hydrogen storage densities. Indeed, an efficient heat transfer (between the tank and its surrounding fluid), a tailored porosity of the metal hydride storage bed and the addition of high thermal conductivity materials allowed the overall storage performance to be improved. Thus, the required time for loading/unloading hydrogen was reduced drastically. The alternation configuration would offer the additional advantage of a simple, inexpensive and efficient recycling procedure.
Date: 9 Sep 2019 - 16:54
Desc: Bacteria adopt social behavior to expand into new territory, led by specialized swarmers, before forming a biofilm. Such mass migration of Bacillus subtilis on a synthetic medium produces hyperbranching dendrites that transiently (equivalent to 4 to 5 generations of growth) maintain a cellular monolayer over long distances, greatly facilitating single-cell gene expression analysis. Paradoxically, while cells in the dendrites (nonswarmers) might be expected to grow exponentially, the rate of swarm expansion is constant, suggesting that some cells are not multiplying. Little attention has been paid to which cells in a swarm are actually multiplying and contributing to the overall biomass. Here, we show in situ that DNA replication, protein translation and peptidoglycan synthesis are primarily restricted to the swarmer cells at dendrite tips. Thus, these specialized cells not only lead the population forward but are apparently the source of all cells in the stems of early dendrites. We developed a simple mathematical model that supports this conclusion. IMPORTANCE: Swarming motility enables rapid coordinated surface translocation of a microbial community, preceding the formation of a biofilm. This movement occurs in thin films and involves specialized swarmer cells localized to a narrow zone at the extreme swarm edge. In the B. subtilis system, using a synthetic medium, the swarm front remains as a cellular monolayer for up to 1.5 cm. Swarmers display high-velocity whirls and vortexing and are often assumed to drive community expansion at the expense of cell growth. Surprisingly, little attention has been paid to which cells in a swarm are actually growing and contributing to the overall biomass. Here, we show that swarmers not only lead the population forward but continue to multiply as a source of all cells in the community. We present a model that explains how exponential growth of only a few cells is compatible with the linear expansion rate of the swarm.
Date: 8 Feb 2017 - 11:24
Desc: no abstract
Date: 3 Jun 2021 - 19:18
Desc: We present a series of microdisk lasers realized within the same GaN-on-Si photonic platform scheme, and operating at room temperature under pulsed optical pumping over a broad spectral range extending over λ = 275 nm–470 nm. The III-nitride microdisks embed either binary GaN/AlN multiple quantum wells (MQWs) for UV operation, or ternary InGaN/GaN MQWs for violet and blue operation. This demonstrates the versatility of this nitride-on-silicon platform, and the realization on this platform of efficient active layers for lasing action over a 200 nm broad UV to visible spectral range. We probe the lasing threshold carrier density over the whole spectral range and found that it is similar whatever the emission wavelength for these Q > 1000 microdisk resonators with a constant material quality until quantum confined Stark effect takes over. The threshold is also found independent of microdisk diameters from 3 to 12 μm, with a β factor intermediate between the one of vertical cavity lasers and the one of small modal volume “thresholdless” lasers.
Université Paris Diderot - Paris 7
U.F.R. Physique
Bâtiment Condorcet
10, rue Alice Domon et Léonie Duquet
75205 PARIS CEDEX 13