Facile method for synthesis of polyaniline/silica hybrid composites by simultaneous sol–gel process and “in situ” polymerization of aniline

The present work describes for the first time a new, simple and environmentally friend procedure for preparing polyaniline/silica hybrid materials by combining the sol–gel method and in situ polymerization of aniline. The hybrid materials were characterized by X-ray diffraction, scanning electron micrography, Fourier transform infrared spectroscopy, ²⁹Si CPMAS solid state nuclear magnetic resonance spectroscopy and thermogravimetric analysis. The hybrids displayed lower electrical conductivity, but higher crystallinity degree than pure PAni. Also electromagnetic interference shielding effectiveness (EMI SE) in the frequency range from 8 to 12 GHz of the hybrid materials containing up to 55 % of silica was similar to that found for pure polyaniline but with higher absorbed power, mainly in lower frequency range. This work demonstrates for the first time that it is possible to obtain PAni/silica-based EMI shielding hybrid materials with similar efficiency as pure polyaniline but with higher thermal stability.