Ref HAL: hal-01747450_v1
DOI: 10.1039/c7nr08457a
WoS: 000428788200002
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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.

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Ref Arxiv: 1711.05777
DOI: 10.1122/1.4997587
WoS: 000414273200022
Ref. & Cit.: NASA ADS
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5 Citations
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We study the fracture of reversible double transient networks, constituted of water suspensions of entangled surfactant wormlike micelles reversibly linked by various amounts of telechelic polymers. We provide a state diagram that delineates the regime of fracture without necking of the filament from the regime where no fracture or break-up has been observed. We show that filaments fracture when stretched at a rate larger than the inverse of the slowest relaxation time of the networks. We quantitatively demonstrate that dissipation processes are not relevant in our experimental conditions and that, depending on the density of nodes in the networks, fracture occurs in the linear viscoelastic regime or in a non-linear regime. In addition, analysis of the crack opening profiles indicates deviations from a parabolic shape close to the crack tip for weakly connected networks. We demonstrate a direct correlation between the amplitude of the deviation from the parabolic shape and the amount of non linear viscoelasticity.

Commentaires: . Réf Journal: Journal of Rheology 61(6), 1267-1275, 2017

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DOI: 10.1021/acs.langmuir.7b00170
WoS: 000399263600013
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A single-drop experiment based on the collision of one drop of liquid on a small solid target is used to produce liquid sheets that are visualized with a fast camera. Upon impact, the drop flattens into a sheet that is bounded by a thicker rim and radially expanding in air. Emulsion-based liquid sheets are destabilized through the nucleation of holes that perforate the sheet during its expansion. The holes grow until they merge together and form a web of ligaments, which are then destabilized into drops. We propose the perforation mechanism as a sequence of two necessary steps. The emulsion oil droplets first enter the air/water interface, and then spread at the interface. We show that the formulation of the emulsion is a critical parameter to control the perforation as the addition of salt or amphiphilic copolymers can trigger or completely inhibit the perforation mechanism. We demonstrate that the entering of the droplets at the air/water interface is the limiting step of the mechanism. Thin-film forces such as electrostatic or steric repulsion forces stabilize the thin film formed between the interface and the approaching oil droplets, thus preventing the entering of droplets at the interface and in turn inhibiting the perforation process. We theoretically rationalize the successive steps in the approach and entering of an oil droplet at the film interface and the role of salt and amphiphilic polymer in the different steps.

Ref HAL: hal-01509535_v1
DOI: 10.1016/j.jcs.2017.04.005
WoS: 000404792200025
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2 Citations
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Model gluten gels