Foam drainage study during plateau border mineralisation

International audienceWe investigate the drainage of a foaming solution during inorganic polycondensation by macroscopic measurements and local observations. We reveal an original mineralisation mechanism starting from Plateau border interfaces. This slow process is not able to counteract the destabilizing effects of foam drainage and we therefore propose a new strategy in which mineralisation is assisted by a biopolymer

A novel three-dimensional macrocellular carbonaceous biofuel cell

Here we report the first membrane-free biofuel cell obtained using three-dimensional carbonaceous foam electrodes. We first developed a new synthetic pathway to produce a new carbonaceous foam electrode material bearing porosity both on the meso and macroporous scales. We proved that by increasing the porosity of our three-dimensional foams we could increase the current density of our modified electrodes. Then, by choosing the right combination of enzyme and mediator, and the right loading of active components, we achieved high current densities for an anodic system. Finally, we combined the improved cathode and anode to build a new membrane-free hybrid enzymatic biofuel cell consisting of a mediated anode and a mediator-free cathode

The Magnetic Spin Ladder (C_{5}H_{12}N)_{2}CuBr_{4}: High Field Magnetization and Scaling Near Quantum Criticality

The magnetization, $M(H \leq 30$ T, 0.7 K $\leq T \leq 300$ K), from single crystals and powder samples of (C$_{5}$H$_{12}$N)$_{2}$CuBr$_{4}$ has been used to identify this system as an $S=1/2$ Heisenberg two-leg ladder in the strong coupling limit, $J_{\perp} = 13.3$ K and $J_{\parallel} = 3.8$ K, with $H_{c1} = 6.6$ T and $H_{c2} = 14.6$ T. An inflection point in $M(H, T = 0.7$ K) at half-saturation, $M_{s}/2$, is described by an effective \emph{XXZ} chain. The data exhibit universal scaling behavior in the vicinity of $H_{c1}$ and $H_{c2}$, indicating the system is near a quantum critical point.Comment: 4 pages, 4 figure

Macrocellular Pd@ionic liquid@organo-Si(HIPE) heterogeneous catalysts and their use for Heck coupling reactions

International audienceSupported ionic liquid phases (SILPs) within macrocellular silica-based foams are prepared by a simple impregnation in organic solvents. Thin ionic liquid layers with thicknesses of 6 to 12 nm were obtained. The SILs mobility has been evidenced through NMR solid state spectroscopy. Subsequently, palladium salts are efficiently trapped within the SILPs, while an in situ palladium hydrogenation allowed an efficient reduction and formation of 10 nm diameter palladium metal nanoparticles. These hybrid foams are used as heterogeneous macrocellular catalysts for the Heck coupling reaction of iodobenzene and cyclohexyl acrylate, where palladium leaching appears to be very low. Despite recyclability minimized through the entrapment of detrimental ammonium salts within the macroporous network during the reaction, competitive TONs and TOFs were reached, while separation of the products can be reached at ease, due to the fact that both palladium species and by-products are trapped within the monolithic foams

Extrusion-based <i>Integrative Chemistry</i>: Generation and applications of inorganic fibers

International audienceIn this review we depict how fibers can be obtained by combining sol-gel and polymer chemistry with extrusion processes acting as an external shaping mode. Thanks to this Integrative Chemistry-based synthetic path, it was possible to organize nano-building blocks such as V2O5 ribbons and ZnO nanorods on a greater length scale yielding highly anisotropic fibers. It has been demonstrated that when aligning a whole population of nano-building block objects along a single main axis, collective properties were obtained, thereby enhancing their sensing, mechanical or photonic properties. This method can be extended toward fiber morphogenesis by using isotropic nanoparticles such as TiO2, and can be scaled-up toward the one-step generation of several hundred meter long fibers with both high surface to volume ratio and high surface roughness. Specifically, when addressing photocatalytic-based VOC pollutant degradation, these TiO2 fibers appear to be outstanding candidates regarding both pollutant degradation and associated mineralization(production of water and carbon dioxide)

Oceanographic biogeochemical sampling and analyses

Trabajo de prácticas de Lucija Backov realizado bajo la dirección del Dr. Francesc Peters del Institut de Ciències del Mar (ICM-CSIC

Biocatalyseurs enzymatiques supportés dédiés à la production en continu de biodiesel

Dossiers Les Techniques de l'Ingénieur IN150Nos sociétés sont confrontées à une demande croissante en combustibles biosourcés non fossiles. Les biodiesels, obtenus par transestérification de triesters, offrent une alternative réelle. Les réactions de transestérification peuvent être catalysées par des enzymes, les lipases. Nous présentons la synthèse de catalyseurs enzymatiques opérant en flux continu. Ces mousses biohybrides offrent de nombreux avantages, un bon confinement des enzymes, un encombrement stérique minimisé, un transport de masse optimisé, une simplicité de synthèse et de mise en oeuvre. Ces spécificités engendrent, pour la production de biodiesel sur supports biohybrides macroporeux, des activités enzymatiques exaltées, associées à des endurances remarquables de catalyses en flux continu

Combining soft matter and soft chemistry: integrative chemistry towards designing novel and complex multiscale architectures

There is today a strong and emerging commitment toward designing complex and hierarchical architectures. In this context, great interest is appearing in the combination of soft chemistry and complex fluids. In any circumstance we can see that there is a strong affinity between soft chemistry and soft matter as they can interact together without disrupting their own function. For instance, a continuous network should emerge from the former while the latter should promote patterning effects. In this general context, the new concept of integrative chemistry is proposed as well as its principle and main perspectives