Effect of γ-PVDF on enhanced thermal conductivity and dielectric property of Fe-rGO incorporated PVDF based flexible nanocomposite film for efficient thermal management and energy storage applications

Here, we investigate the effect of thermal conductivity of gamma-crystallites of PVDF in Fe-rGO/PVDF nanocomposite, which are of potential use as actuators and temperature sensors for thermal management applications. The formation of gamma-crystallites help to increase the thermal conductivity of the nanocomposite up to 0.89 W mK(-1) at low level of filler loading (3 wt%) and we showed that the thermal conductivity depends on the amount of crystalline polar gamma-phase in addition to filler concentration. Although thermal conductivity depends on the crystallinity of the nanocomposite, here enhancement of thermal conductivity is not related only to crystallinity, as the crystallinity is decreased compared to neat PVDF. However the thermal conductivity increases because of the generation of a higher number of gamma-crystallites of small size. Furthermore, the nanocomposite at low filler loading also shows high dielectric constant with low dielectric loss of the order of approximate to 57 and approximate to 0.13, respectively, at 1 kHz. Moreover, the energy storage property and its dependence on gamma-crystallite size reveals that the material can also exhibit superior released energy density (1.45 J cm(-3)) as compared to pure PVDF.