Synthesis of optical transparent and electrical conductive polymer/nanocarbon composite films by infiltration method

Optical transparent and electrical conductive (PMMA)/nanocarbon composite films can be prepared through the infiltration of the polymer between the carbon aggregates of a preformed percolation cluster. This cluster is prepared by Langmuir-Blodgett technique as a thick film (2-20 μm in thickness). The performed direct current electrical measurements have shown that PMMA/Multiwall Nanotubes present a lower electrical surface resistivity and a higher optical transmittance than PMMA/carbon nanoparticles composite films. Much simpler and cheaper than other methods, the infiltration method allowed us to prepare composite films with a 75% in transparency and 1 MΩ/square in surface electrical resistivity. The composite films prepared by infiltration method have a good adhesion to the glass substrates but in some specific conditions can be integrally removed as free-standing films.     

Structural and sensing properties of a novel Fe/Fe2O3/polyoxocarbosilane core shell nanocomposite powder prepared by laser pyrolysis

This paper reports about the synthesis and characterization of a novel Fe/Fe₂O₃/polyoxocarbosilane core shell nanocomposite as a material for gas-sensing applications. The nanocomposites (Fe-based nano cores enveloped with polymeric polyoxocarbosilane shells) were prepared by the IR laser co-pyrolysis of iron pentacarbonyl and hexamethyldisiloxane. The iron-based cores become superficially oxidized in atmosphere. The morphologies, chemical content and thermal behavior were studied by different analytical techniques. The sensing properties of the polymer-poor nanocomposite thick films were tested by measuring the variation of the electrical resistance in presence of CO and CH₄, at a working temperature of 450 °C. Preliminary results indicate that for CO toxic gas, an n–p transitional character of the semiconducting iron oxide appears in humid relatively to dry air.