Thermal conductivity of graphene oxide-enhanced polyvinyl alcohol composites depending on molecular interaction

Abstract

Graphene oxide (GO) synthesized from graphite via oxidation and exfoliation is a graphene-like single-layer sheet with numerous oxygen groups and defects on the basal plane. In this study, GO is added as a filler in the polyvinyl alcohol (PVA) matrix for the purpose of improving thermal conductivity. GO is well dispersed in PVA aqueous solution, and GO/PVA composite films are easily prepared with various GO contents. The thermal conductivities of the polymer composites investigated in terms of GO content concentration, GO degree of oxidation, PVA degree of polymerization, and silica-bead packing in the GO/PVA composite. On the basis of phonon mean free path, the effect of oxygen groups in GO is discussed in relation to crystallinity of PVA and molecular interaction between GO and PVA. In addition, the phonon conductive path along the direction of thickness in the GO/PVA composite film is achieved via silica-bead packing.