Enhancement of the electrochemical performance of SWCNT dispersed in a Silica Sol-Gel matrix by reactive Insertion of a Conducting Polymer

The electroassisted encapsulation of Single-Walled Carbon Nanotubes was performed into silica matrices (SWCNT@SiO2). This material was used as the host for the potentiostatic growth of polyaniline (PANI) to yield a hybrid nanocomposite electrode, which was then characterized by both electrochemical and imaging techniques. The electrochemical properties of the SWCNT@SiO2-PANI composite material were tested against inorganic (Fe3+/Fe2+) and organic (dopamine) redox probes. It was observed that the electron transfer constants for the electrochemical reactions increased significantly when a dispersion of either SWCNT or PANI was carried out inside of the SiO2 matrix. However, the best results were obtained when polyaniline was grown through the pores of the SWCNT@SiO2 material. The enhanced reversibility of the redox reactions was ascribed to the synergy between the two electrocatalytic components (SWCNTs and PANI) of the composite material. (C) 2014 Elsevier Ltd. All rights reserved.This work was financed by the following research projects: MAT2010-15273 of the Spanish Ministerio de Economia y Competitividad and CIVP16A1821 of the Fundacion Ramon Areces and PROMETEO 2013/038 of the Generalitat Valenciana. Alonso Gamero-Quijano is grateful to Generalitat Valenciana (Santiago Grisolia Program) for the funding of his research fellowship. David Salinas-Torres is grateful to Ministerio de Economia y Competitividad for the funding of his research fellowship.Gamero-Quijano, A.; Huerta, F.; Salinas Torres, D.; Morallón, E.; Montilla, F. (2014). Enhancement of the electrochemical performance of SWCNT dispersed in a Silica Sol-Gel matrix by reactive Insertion of a Conducting Polymer. Electrochimica Acta. 135:114-120. https://doi.org/10.1016/j.electacta.2014.04.172S11412013

Magnetodielectric effect of Graphene-PVA Nanocomposites

Graphene-Polyvinyl alcohol (PVA) nanocomposite films with thickness $120 \mu m$ were synthesized by solidification of PVA in a solution with dispersed graphene nanosheets. Electrical conductivity data were explained as arising due to hopping of carriers between localized states formed at the graphene-PVA interface. Dielectric permittivity data as a function of frequency indicated the occurrence of Debye-type relaxation mechanism. The nanocomposites showed a magnetodielectric effect with the dielectric constant changing by 1.8% as the magnetic field was increased to 1 Tesla. The effect was explained as arising due to Maxwell-Wagner polarization as applied to an inhomogeneous two-dimensional,two-component composite model. This type of nanocomposite may be suitable for applications involving nanogenerators.Comment: 13 pages, 11 figure

Models for nanoindentation of compliant films on stiff substrates

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