Largely enhanced thermal conductivity of poly(vinylidene fluoride)/carbon nanotube composites achieved by adding graphene oxide

A small amount of graphene oxide (GO) was introduced into poly(vinylidene fluoride) (PVDF)/carbon nanotube (CNT) composites through solution compounding. The thermal conductivity, crystallization behavior of PVDF matrix, and the dispersion states of CNTs and/or CNT/GO in the PVDF composites were comparatively investigated. The results demonstrated that with the presence of only 1 wt% GO, the PVDF/CNT/GO composites exhibited largely enhanced thermal conductivity compared with the PVDF/CNT composites at the same CNT content. Although the crystallinity of matrix in the PVDF/CNT/GO composites is apparently decreased in comparison with that in the PVDF/CNT composites, a large number of polar gamma-form crystallites were induced. The presence of GO facilitated the dispersion of CNTs and the formation of denser CNT/GO network structure in the PVDF matrix. The theoretical simulation further demonstrated the experimental observations. The mechanisms for the largely enhanced thermal conductivity of the PVDF/CNT/GO composites were then analyzed. (C) 2015 Elsevier Ltd. All rights reserved.