Conduction mechanism and dielectric properties of pure and composite resorcinol formaldehyde aerogels doped with silver

Abstract

Pure and composite Resorcinol–Formaldehyde (RF) aerogel samples were prepared by sol-gel process using KOH as a catalyst and doped with silver nanoparticles at different concentrations (1.2×10-4, 2.4×10-4, 3.6×10-4, and 4.8×10-4 wt.% at catalyst ratio 0.024 wt.%). DC electrical conductivity σdc, AC electrical conductivity σ′, and the dielectric properties of the prepared samples have been measured at different frequencies and temperatures. The results show that σ′ increases with increasing frequency. The values of σ′ range from ∼10-4 Ω-1m-1 to around unity at room temperature. The analysis of the results of σ′(ω, T) reveals that the large overlapping polaron (OLP) is the most favorable mechanism to describe the conduction mechanism in these samples. The behavior of the dielectric constant with the frequency of these samples is normal, where it decreases with increasing frequency, while the behavior of dielectric loss tangent tanδ exhibits a peaking behavior at relatively higher temperature.