Influence of graphene oxide and reduced graphene oxide on TiO2-reinforced flexible poly(vinyl alcohol) films for electromagnetic interference shielding

Abstract

This study evaluates the impact of graphene oxide (GO) and reduced graphene oxide (rGO) on the structural characteristics and electromagnetic interference shielding effectiveness (EMI SE) of poly(vinyl alcohol) (PVA) films containing titanium dioxide (TiO₂). The composite films were prepared by solution casting, and their structural properties were analyzed through FTIR, electron microscopy, and X-ray diffraction. EMI SE was evaluated as a function of GO and rGO concentrations. Spectroscopic data indicated that TiO₂ and GO interact with PVA primarily through hydrogen bonding. The inclusion of TiO₂ increased the crystallinity of the films, although its interaction with PVA was not uniform. In composites containing GO, TiO₂ exhibited enhanced affinity for the polymer matrix due to the hydrophilic nature of both components. As a result, GO influenced the action of TiO₂ in the composite, leading to EMI SE values of 3.27 dB/mm in the X-band and 7.28 dB/mm at 9.3 GHz. The addition of rGO led to reduced interaction with TiO₂ due to a lower content of oxygen-containing groups, with the higher electrical conductivity of rGO being the most prominent effect observed. rGO demonstrated a competitive effect at 1% filler and a synergistic effect at 4% filler, with EMI SE values at 9.9 GHz increasing to 31.34 dB/mm and 55.80 dB/mm, respectively. This study shows that GO/TiO₂/PVA and rGO/TiO₂/PVA composite films exhibit promising EMI shielding properties. The different interactions between GO and rGO with TiO₂ and PVA result in distinct EMI SE mechanisms, with rGO showing superior performance. Combined with excellent mechanical flexibility and relatively low thickness, these data highlight the potential of these composite films for EMI shielding applications.