Through-plane high thermal conducting networks via incorporation of graphene nanoplatelets in nanocomposite film under electric field and avoiding breakdown voltage

Abstract

Electric field inducement technology is one of the most efficient and straightforward way to direct and form a percolation network of conducting fillers in a polymer without necessitating chemical functionalization. However, extended application is very restricted due to the initiation of electrical breakdown of conducting fillers in polymers. Herein, thermal conductive polymer nanocomposites are fabricated using graphene nanoplatelets (GNP) as a conducting filler under application of electric field that avoids electric breakdown. An electrode surface is coated with fuluoacrylate of nano-to-micro-dimensional thickness, which is applied as insulating electrodes to inhibit electric spark under application of electric current. Two different kinds of electric fields; direct current (DC) and switching DC (SWDC), were applied to envisage the enhancement of filler assembly. Analysis showed that an insulating layer with approximately 0.35–18 μm of thickness was successfully coated on the electrodes, which enabled increased formation of through-plane thermal conducting networks as well as enhanced thermal conductivity compared to composites with random filler distribution. The intensity of the available electric field could be increased over 30 times without breakdown with the insulating layer. Moreover, the field-induced GNP assembly generated by SWDC improved the thermal conductivity of the composite of over 112% compared to composite with random GNP distribution. This technique has the potential to control the linear assembly of conducting fillers an under electric field without electric breakdown.