Electrospraying Graphene Nanosheets on Polyvinyl Alcohol Nanofibers for Efficient Thermal Management Materials

With the rapid development of electronic devices, the demand for heat-dissipating materials is increasing. Graphene is a two-dimensional (2D) material with high thermal conductivity. In this study, reduced graphene oxide (rGO) nanosheets are electrostatically sprayed on the surface of electrospun polyvinyl alcohol (PVA) nanofibers. A multilayer rGO/PVA film is fabricated by performing multi-step electrospinning and electrospraying. Finally, the multilayer rGO/PVA films are cut into small pieces and stacked for hot pressing to obtain a flexible H-rGO/PVA-t film (where t denotes the rGO-layer electrospraying time). Scanning electron microscopy images show that an rGO-layer electrospraying time of 4 h resulted in a uniform distribution of rGO sheets on the PVA nanofiber surface to form continuous heat transfer channels. Hence, the H-rGO/PVA-4 composite exhibits high in-plane and cross-plane thermal conductivities of 6.15 and 0.89 W m–1 K–1, respectively, and can be used as a thermal-interface material (TIM) to facilitate effective thermal management. Compared to a hot-pressed pure PVA film, the H-rGO/PVA-4 TIM facilitates a lower surface temperature for light-emitting diode (LED) lamps. This study provides a universal approach for fabricating heat-dissipating composites of 2D materials and polymer films.