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Production scientifique
Matière Molle
(421) Articles dans des revues
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Customised bifurcating networks for mapping polymer dynamics in shear flows
Auteur(s): Fidalgo Joana, Zografos Konstantinos, Casanellas Vilageliu L., Lindner Anke, Oliveira Mónica
(Article) Publié:
Biomicrofluidics, vol. 11 p. (2017)
Texte intégral en Openaccess :
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Formulation flottante de biopesticide pour une démoustication efficace et durable
Auteur(s): Massiera G.
(Article) Publié:
Les Cahiers De La Recherche Santé, Environnement, Travail, vol. p.16-17 (2017)
Ref HAL: anses-01798647_v1
Exporter : BibTex | endNote
Résumé: 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.
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Swollen hexagonal liquid crystals as smart nanoreactors: implementation in materials chemistry for energy applications
Auteur(s): Ghosh Srabanti, Ramos L., Remita Hynd
(Article) Publié:
Nanoscale, vol. 10 p.5793-5819 (2018)
Ref HAL: hal-01747450_v1
DOI: 10.1039/c7nr08457a
WoS: 000428788200002
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11 Citations
Résumé: 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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Phase transfer of TiO2 nanoparticles from water to ionic liquid triggered by phosphonic acid grafting
Auteur(s): Bhandary R., Alauzun J. G., Hesemann Peter, Stocco A., In M., Mutin P. Hubert
(Article) Publié:
Soft Matter, vol. 13 p.8023 - 8026 (2017)
Ref HAL: hal-01653105_v1
DOI: 10.1039/c7sm01424d
WoS: 000415352100002
Exporter : BibTex | endNote
11 Citations
Résumé: Controlling the interface between TiO2 nanocrystals and ionic liquids is of high fundamental and applied interest for energy storage and conversion devices. Phase transfer of nanoparticles from a synthesis medium to a processing or an application medium plays a significant role in nanotechnology. Here we demonstrate that surface modification with phosphonic acids bearing cationic end-groups can trigger the phase transfer of TiO2 nanoparticles from an aqueous sol to a typical water-immiscible ionic liquid, [Emim][NTf2]. The transfer involves both the grafting of the phosphonic acid moiety and the exchange of the counter ion of the cationic end-group by NTf2 anions, as demonstrated by solid-state NMR, elemental analysis and independent grafting and ion exchange experiments. Furthermore, the colloidal stability of the TiO2 sols in [Emim][NTf2] strongly depends on the hydrophobic character of the cationic end-groups.
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In situ AFM investigation of slow crack propagation mechanisms in a glassy polymer
Auteur(s): George M., Nziakou Y. K., Goerke S., Genix A.-C., Bresson Bruno, Roux Stéphane, Delacroix H., Halary J.-L., Ciccotti M.
(Article) Publié:
Journal Of The Mechanics And Physics Of Solids, vol. 112 p.109-125 (2018)
Texte intégral en Openaccess :
Ref HAL: hal-01656192_v1
DOI: 10.1016/j.jmps.2017.11.019
WoS: 000426536400006
Exporter : BibTex | endNote
2 Citations
Résumé: A novel experimental technique based on in situ AFM monitoring of the mechanisms of damage and the strain fields associated to the slow steady-state propagation of a fracture in glassy polymers is presented. This micron-scale investigation is complemented by optical measurements of the sample deformation up to the millimetric macroscopic scale of the sample in order to assess the proper crack driving conditions. These multi-scale observations provide important insights towards the modeling of the fracture toughness of glassy polymers and its relationship with the macromolecular structure and non-linear rheological properties. This novel technique is first tested on a standard PMMA thermoplastic in order to both evaluate its performance and the richness of this new kind of observations. Although the fracture propagation in PMMA is well known to proceed through crazing in the bulk of the samples, our observations provide a clear description and quantitative evaluation of a change of fracture mechanism towards shear yielding fracture accompanied by local necking close to the free surface of the sample, which can be explained by the local change of stress triaxiality. Moreover , this primary surface necking mechanism is shown to be accompanied by a network of secondary grooves that can be related to surface crazes propagating towards the interior of the sample. This overall scenario is validated by post-mortem fractographic investigations by scanning electron microscopy.
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Janus Colloids Actively Rotating on the Surface of Water
Auteur(s): Wang X., In M., Blanc C., Würger Aloïs, Nobili M., Stocco A.
(Article) Publié:
Langmuir, vol. 33 p.13766 - 13773 (2017)
Texte intégral en Openaccess :
Ref HAL: hal-01664755_v1
DOI: 10.1021/acs.langmuir.7b02353
WoS: 000416877600006
Exporter : BibTex | endNote
21 Citations
Résumé: Biological or artificial microswimmers move performing trajectories of different kinds such as rectilinear, circular, or spiral ones. Here, we report on circular trajectories observed for active Janus colloids trapped at the air−water interface. Circular motion is due to asymmetric and nonuni form surface properties of the particles caused by fabrication. Motion persistence is enhanced by the partial wetted state of the Janus particles actively moving in two dimensions at the air−water interface. The slowing down of in plane and out of plane rotational diffusions is described and discussed.
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A model for failure in thermoplastic elastomers based on Eyring kinetics and network connectivity
Auteur(s): Aime S., Eisenmenger N. D., Engels T. A. P.
(Article) Publié:
Journal Of Rheology / Transactions Of The Society Of Rheology; Society Of Rheology -- Transactions, vol. 61 p.1329-1342 (2017)
Texte intégral en Openaccess :
Ref HAL: hal-01653311_v1
DOI: 10.1122/1.5000808
WoS: WOS:000414273200030
Exporter : BibTex | endNote
4 Citations
Résumé: A simple model is introduced to describe the failure mechanisms in soft thermoplastic elastomers. In particular, we address the strong embrittlement with increasing temperature observed in strain rate imposed tensile experiments. This behavior is in sharp contrast to classic thermoplastics and seems to be general for these types of systems, irrespective of their exact chemical nature. We show that a kinetic model describing the supramolecular association of hard blocks in terms of an Eyring rate equation captures the correct stress and temperature dependence of failure strain. We model the material as a transient network, whose failure is associated with the loss of connectivity. The network percolation threshold, a key parameter of the model, is studied with numerical simulations, in order to investigate the interplay between structure, connectivity, and mechanical properties.
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