The Fine and Fractal Structure and Protonic Conductivity of Phosphosilicate-Diamond Sol-Gel Nanocomposites

Abstract

Composite xerogels based on a phosphosilicate matrix filled with nanodiamonds were synthesized by sol-gel processing. The crystalline and fractal characteristics of the initial nanopowders were obtained using wide-angle X-ray scattering (WAXS) and small-angle X-ray scattering (SAXS) techniques. Proton-conducting nanocomposite membranes of fuel cell applications were fabricated from the xerogels. The WAXS data on the nanodiamonds show diffraction patterns characteristic of graphitized ultradisperse nanodiamonds or pure nanodiamonds. The Beaucage plots of the phosphosilicate-nanodiamond composites show a multi-level fractal structure of the type of the surface fractal/mass fractal. The fractal characteristics such as the size and the gyration radius of the aggregates were calculated from the plots. The conductivity-frequency curves show that the conductivity is high and increases with the nanodiamond content in the composites.