Silica particles wrapped with poly(aniline-co-pyrrole) and reduced graphene oxide for advanced microwave absorption

Abstract

In this work, a novel nanocomposite composed of silica nanoparticles wrapped with a poly(aniline-co-pyrrole) copolymer and reduced graphene oxide (P(ANi-co-Py)/RGO@SiO2) was prepared by an in situ pre-polymerization method and then characterized. The aniline:pyrrole molar ratio was 1:3 and the pre-polymerization time was 30 min before the in situ polymerization of the copolymer nanocomposites occurred. The results revealed that the microwave absorbing performance of the copolymer nanocomposites was significantly improved compared to that of the component homopolymer nanocomposites. The minimum reflection loss of P(ANi-co-Py)/RGO@SiO2, PANi/RGO@SiO2, and PPy/RGO@SiO2 was −40.6, −38.9, and −13.9 dB, respectively. The effective absorption bandwidth of P(ANi-co-Py)/RGO@SiO2 was 5.5 GHz from 12.3 to 17.8 GHz. In contrast, the effective absorption bandwidth of a component homopolymer nanocomposite, such as PANi/RGO@SiO2, was 2.2 GHz (15.8–18 GHz), and for PPy/RGO@SiO2, was only 1.5 GHz (12.4–13 GHz and 16.7–17.6 GHz) in Ku band. The enhanced microwave absorption was mainly contributed to the interfacial polarization in which the interfacial interaction between SiO2 particles, rGO sheets and conducting polymer chains played critical roles.