Surfactant solutions exhibit multilamellar surfactant vesicles (MLVs) under flow conditions and in concentration ranges which are found in a large number of industrial applications. MLVs are typically formed from a lamellar phase and play an important role in determining the rheological properties of surfactant solutions. Despite the wide literature on the collective dynamics of flowing MLVs, investigations into the flow behavior of single MLVs are scarce. In this work, we investigate a concentrated aqueous solution of linear alkylbenzene sulfonic acid (HLAS), characterized by MLVs dispersed in an isotropic micellar phase. Rheological tests show that the HLAS solution is a shear-thinning fluid with a power law index dependent on the shear rate. Pressure-driven shear flow of the HLAS solution in glass capillaries is investigated using high-speed video microscopy and image analysis. The so obtained velocity profiles provide evidence for a power-law fluid behaviour of the HLAS solution and images show a flow-focusing effect of the lamellar phase in the central core of the capillary. The flow behavior of individual MLVs shows analogies with that of unilamellar vesicles and emulsion droplets. Deformed MLVs exhibit typical shapes of unilamellar vesicles, such as parachute and bullet-like. Furthermore, MLV velocity follows the classical Hetsroni theory for droplets provided that the power law shear dependent viscosity of the HLAS solution is taken into account. The results of this work are relevant for the processing of surfactant-based systems in which the final properties depend on the flow-induced morphology, such as cosmetic formulations and food products.

The physics of microemulsions and in particular Dominique Langevin's contributions to the understanding of microemulsion structure and bending properties using scattering techniques are reviewed. Among the many methods used by her and her co-workers, we particularly emphasize optical techniques and small angle neutron scattering, but also neutron spin echo spec-troscopy. The review is then extended to more recent studies of properties of microemulsions close to surfaces, using reflectometry and grazing-incidence small angle neutron scattering (GISANS).

We investigate the spontaneous restructuring andaging behavior of pig gastric mucus gels by combining rheology andnonconventional static and dynamic light scattering. We find that themucus elasticity weakens over time, concomitantly to structuralevolution toward a locally more compact configuration and the onsetof large scale density fluctuations. We interpret this behavior asstemming from an arrested phase separation, as observed in manygel-forming polymer systems. This scenario is confirmed by spaceandtime-resolved dynamic light scattering data, showing that the gelrestructuring is due to intermittent bursts of spatially correlatedrearrangements, leading to ballistic dynamics.

L’observation de résistances chez certaines espèces de moustiques aux pesticides synthétiques les plus couramment utilisés a conduit à l’utilisation et au développement d’alternatives efficaces aux insecticides chimiques. Ainsi, l’insecticide d’origine bactérienne Bacillus thuringiensis israelensis (Bti) est devenu pratiquement la seule substance active autorisée pour le traitement des gîtes larvaires de moustiques en milieu naturel en France métropolitaine. Si le Bti est un biolarvicide intéressant, son efficacité dépend de sa présence et de sa rémanence à la surface de l’eau, c’est‐à‐dire là où les larves de moustiques se nourrissent, exclusivement pour certaines espèces anophèles. Le projet de recherche "MicroBti" consiste à étudier deux stratégies de formulation qui permettraient de prolonger la présence de Bti à la surface de l’eau au-delà de quelques jours (à l’exception des eaux usées), pour le traitement des gîtes larvaires.

Materials are the key roadblocks for the commercialization of energy conversion devices in fuel cells andsolar cells. Significant research has focused on tuning the intrinsic properties of materials at the nanometerscale. The soft template mediated controlled fabrication of advanced nanostructured materials isattracting considerable interest due to the promising applications of these materials in catalysis and electrocatalysis.Swollen hexagonal lyotropic liquid crystals (SLCs) consist of oil-swollen surfactant-stabilized1D, 2D or 3D nanometric assemblies regularly arranged in an aqueous solvent. Interestingly, the characteristicsize of the SLCs can be controlled by adjusting the volume ratio of oil to water. The non-polarand/or polar compartments of the SLCs can be doped with guest molecules and used as nanoreactorsfor the synthesis of various metals (Pt, Pd, Au, etc.), conducting polymers and composite nanostructureswith controlled size and shape. 1D, 2D and 3D mono- and bimetallic nanostructures of controlled compositionand porosity can also be fabricated. These materials have demonstrated impressive enhancementsof their electrochemical properties as compared to their bulk counterparts and have been identifiedas promising for further implementation in energy harvesting applications. In this review article,recent research materials are described regarding the development of functional materials with muchimproved performances for catalysis applications. This review addresses a brief overview of swollen hexagonalmesophases as nanoreactors, describes examples of nanostructured materials synthesized inthese nanoreactors, shows several examples of the energy conversion applications in solar light harvesting,fuel cells etc. and also summarizes the associated reaction mechanisms developed in the recent literaturefor enhanced catalytic activity.