Radio frequency heating and reduction of Graphene Oxide and Graphene Oxide - Polyvinyl Alcohol Composites

Abstract

Graphene oxide (GO) is one of the most frequently-used graphene-family materials, but it must often be reduced in order to restore electrical conductivity for the target applications. We have demonstrated the use of non-contact fringing field RF applicators to rapidly heat and reduce GO, both in its neat form and inside a polymer matrix such as polyvinyl alcohol (PVA). For this study, GO and GO-PVA films were prepared by the vacuum filtration method. The results demonstrate quick non-contact heating of GO and GO-PVA composite films by application of RF fields. Heating rates as high as 10.9 °C/s and 1.5 °C/s have been observed for GO and GO-PVA, respectively. RF-reduced GO and GO-PVA samples have shown conductivities of 102 S/m and 10−1 S/m, respectively. In addition, C/O ratio has increased from 2.44 to 5.22 when GO is exposed to RF waves which confirm that GO samples are reduced by the RF treatment. Unlike time-consuming or hazardous conventional reduction methods, RF waves resistively heat GO with electric fields in seconds to form reduced GO.