The Experts below are selected from a list of 255 Experts worldwide ranked by ideXlab platform

Hyun-joong Kim - One of the best experts on this subject based on the ideXlab platform.

Josik Portier - One of the best experts on this subject based on the ideXlab platform.

  • TiO2–Polymer Nano–Composites by Sol–Gel
    Active and Passive Electronic Components, 1995
    Co-Authors: A. C. Pierre, G. Campet, S. Y. Huang, Etienne Duguet, Josik Portier
    Abstract:

    Sol-gel processes make it possible to develop new hybrid electrolyte materials of the type ceramic-Polymer, known as Nano-Crystallite-Insertion-Material (NCIM). They can be used in reversible alkali electrochemical cells after insertion with cations such as Li+. In the present study, TiO2-polyethylene oxide hybrid materials were synthesized from TiCl4 and from Ti ethoxide. Their structure is analyzed in relation with the processing parameters. A primary evaluation of the nanoscale composite materials for reversible Li insertion was performed.

  • TiO2-Polymer Nano-Composites by sol-gel
    Journal of Sol-Gel Science and Technology, 1994
    Co-Authors: A. C. Pierre, G. Campet, Etienne Duguet, Josik Portier
    Abstract:

    Sol-gel processes make it possible to develop new hybrid electrolyte materials of the type ceramicPolymer, known as Nano-Crystallite-Insertion-Material (NCIM). They can be used in reversible alkali electrochemical cells after insertion with cations such as Li+. In the present study, TiO2-polyethylene oxide hybrid materials were synthesized, from TiCl4 and from Ti ethoxide. Their structure is analyzed in relation with the processing parameters. A primary evaluation of the nanoscale composite materials for reversible Li insertion was done.

Vincent Gaud - One of the best experts on this subject based on the ideXlab platform.

  • Inorganic/organic nanocomposites: Reaching a high filler content without increasing viscosity using core-shell structured nanoparticles
    Applied Physics Letters, 2015
    Co-Authors: Warda Benhadjala, M. Gravoueille, M. Louarn, Isabelle Bord-majek, Laurent Béchou, Ephraim Suhir, Matthieu Buet, Fabien Rougé, M. Weiss, Vincent Gaud
    Abstract:

    Extensive research is being conducted on the development of inorganic/organic nanocomposites for a wide variety of applications in microelectronics, biotechnologies, photonics, adhesives, or optical coatings. High filler contents are usually required to fully optimize the nanocomposites properties. However, numerous studies demonstrated that traditional composite viscosity increases with increasing the filler concentration reducing therefore significantly the material processability. In this work, we synthesized inorganic/organic core-shell nanocomposites with different shell thicknesses. By reducing the shell thickness while maintaining a constant core size, the nanopar-ticle molecular mass decreases but the nanocomposite filler fraction is correlatively increased. We performed viscosity measurements, which clearly highlighted that intrinsic viscosity of hybrid nanoparticles decreases as the molecular mass decreases, and thus, as the filler fraction increases, as opposed to Einstein predictions about the viscosity of traditional inorganic/Polymer two-phase mixtures. This exceptional behavior, modeled by Mark-Houwink-Sakurada equation, proves to be a significant breakthrough for the development of industrializable nanocomposites with high filler contents. V C 2015 AIP Publishing LLC. [http://dx.doi.org/10.1063/1.4936339] Given increasing environmental issues, the idea of replac-ing inorganic materials with Polymer-based nanocomposites has attracted strong interest in a wide variety of applications, including microelectronics, photonics, (renewable) energy, and biotechnologies. 1 For example, ceramic/Polymer nanocom-posites which combine the mechanical properties of Polymers with the high permittivity of ceramics provide excellent candidates as dielectric materials. 2 Alternatively, conducting metal/Polymer composites exhibit electrical performances close to those of pure metals while their mechanical properties and processing methods are typical of plastics. 3 Polymer Nano-Composites constitute indeed a new class of materials with enhanced mechanical and functional properties. Above all, they are more environmentally friendly and less expensive to pro-cess than inorganic materials, and thus particularly attractive for industry purposes. The nanosized composites are tradition-ally prepared by incorporating inorganic nanopowders (the fill-ers) in a Polymer matrix. According to physical models for predicting composites properties (e.g., Bruggeman, Landauer, and Jayasundere equations), high filler volume fraction is required to achieve optimized performances. 4 However, increasing the filler concentration favors the agglomeration of the nanopowders and leads to an increase in the viscosity as predicted by Einstein over a century ago. 5 This classical rheo-logical model has been experimentally verified for the vast ma-jority of inorganic/organic hybrid materials. 6 Highly filled nanocomposites with improved functional properties are unsuit-able for industrial processes where the material viscosity and uniformity act as prominent parameters. 7 It becomes, therefore, extremely challenging to develop uniformly dispersed Polymer nanocomposites with a high filler fraction and a low viscosity. Hence, as described later, we studied unique systems con-sisting of hybrid nanoparticles with a core-shell structure. This type of nanostructure has been extensively investigated in very recent years since it offers the possibility to obtain inorganic-organic nanocomposites without the need of addi-tional matrix or particle modifiers. Homogeneous dispersions have been observed for diverse combinations of hybrid nanoparticles. 8,9 However, viscosity properties of core-shell nanocomposites have been rarely described. In this article, we report on the outstanding viscosity properties of core-shell structured inorganic-hyperbranched Polymer nanocomposites. The hybrid nanocomposites consist of spherical barium tita-nate (BaTiO 3) nanoparticles (100 nm) blended with a hyper-branched polyester poliol shell which is then end-capped by methacrylate functions (Fig. 1). 9 BaTiO 3 -Polymer composites are currently of strong interest especially for dielectric applications. 2,9 Dendritic Polymers such as hyperbranched Polymers exhibit lower viscosity compared with linear Polymers with same molecular mass and similar chemical structure.

Jitendra K Pandey - One of the best experts on this subject based on the ideXlab platform.

J. Yang - One of the best experts on this subject based on the ideXlab platform.

  • Positron Annihilation Studies In Polymer Nano‐Composites
    2011
    Co-Authors: Hongmin Chen, Somia Awad, Yan-ching Jean, J. Yang
    Abstract:

    Positron annihilation spectroscopy coupled with a variable mono‐energy positron beam has been applied to study nanoscale Polymeric nanocomposites. New information about multilayer depth profiles and structures, interfacial free‐volume and open space properties have been obtained in polystyrene/carbon nano fiber composites. The S parameter in Doppler Broadening Energy Spectra combined slow positron beam is used to quantitatively represent the free volume, open spaces, and interactions in the interface between polystyrene matrix and carbon nanofibers.

  • Positron annihilation study in inorganic-Polymer Nano-Composites
    Physica Status Solidi (c), 2009
    Co-Authors: Hongmin Chen, Yan-ching Jean, J. Yang, James Huang
    Abstract:

    Positron annihilation lifetime experiments in a series of polystyrene (PS) Nano-Composites of different wt% of SiO2 as a function of temperature have been performed and the glass transition temperatures are determined. Previously, in PS/CNF(carbon nanofiber), a system with strong interfacial bonding, we found single glass transition temperature (Tg), which increases with wt% of CNF. Currently, in PS/SiO2 Nano-Composites, a weak interfacial interaction system, we found that there are two Tgs, one at 57 oC, which is lower than the PS bulk Tg (= 91 °C). The lower Tg is interpreted from the free volume in the weak bonding interface between PS and SiO2. This result is consistent with our previous slow positron beam results of PS on Si substrate, which shows a significant lower Tg in the interface than in the bulk PS. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim)