Effect of plasma modification on the dispersion of high thermal conductive nano-filler

With the development of high voltage engineering and microelectronic products, insulating materials with high thermal conductivity are demanded urgently. Epoxy resin (ER) is one of the widely used polymer for insulating materials. However, the thermal conductivity of ER is low, which limits the application in the area requiring heat dissipation. In general, adding inorganic filler with high thermal conductivity into ER is a solution to increase the thermal conductivity of the composites. In this solution, the dispersion and stability of filler is the key for the fabrication of composites. In this paper, the plasma modification of fillers (alumina nanoparticles) is investigated. The fillers are modified in gas discharge and gas-liquid discharge, respectively. The dispersion of filler is evaluated before and after modification by Zeta potential. After DBD modification for 6 min, the dispersion of alumina nanoparticles in water increased with 113% at zeta potential. After discharge in gas-liquid environment, the particle size changes relatively. This may be caused by the introduction of functional groups and covalent bonds on the surface of the filler by plasma modification. This study provides key support for the mass production of nano-filler for high voltage insulation.