Hopping conduction on PPy/SiO2 nanocomposites obtained via in situ emulsion polymerization

This work describes the preparation and electrical characterization of conducting polypyrrole (PPy) and silica nanocomposites. Four samples were investigated: (i) pure PPy, (ii) PPy-covered SiO2 spherical nanoparticles, (iii) PPy-covered SiO2 spherical nanoparticles modified with 3-aminopropyltriethoxysilane (APS), and (iv) PPycovered SiO2 fibers. Structural characterization was made by scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The electrical conductivity was measured from 80 K to 300 K and three-dimensional variable range hopping conduction was observed. From the hopping parameter the mean hopping distance was obtained as well as the density of active center and the energy associated with it