Enhanced Thermal Conductivity in Oriented Polyvinyl Alcohol/Graphene Oxide Composites.

Polymer composites have attracted increasing interest as thermal management materials for use in devices owing to their ease of processing and potential lower costs. However, most polymer composites have only modest thermal conductivities, even at high concentrations of additives, resulting in high costs and reduced mechanical properties, which limit their applications. To achieve high thermally conductive polymer materials with a low concentration of additives, anisotropic, solid-state drawn composite films were prepared using water-soluble polyvinyl alcohol (PVA) and dispersible graphene oxide (GO). A co-additive (sodium dodecyl benzenesulfonate) was used to improve both the dispersion of GO and consequently the thermal conductivity. The hydrogen bonding between GO and PVA and the simultaneous alignment of GO and PVA in drawn composite films contribute to an improved thermal conductivity (∼25 W m-1 K-1), which is higher than most reported polymer composites and an approximately 50-fold enhancement over isotropic PVA (0.3-0.5 W m-1 K-1). This work provides a new method for preparing water-processable, drawn polymer composite films with high thermal conductivity, which may be useful for thermal management applications.