Effect of plasma modified nanoparticles on trap level distribution and dielectric properties of nanocomposites

In order to enhance the compatibility between nanoparticles and polymer matrices, surface modification of AI₂O₃ nanoparticles was conducted by non-thermal plasma, before in-situ polymerization was used to prepared polyimide/Al₂O₃ nanocomposite films. In the nanocomposites prepared with plasma treated nanoparticles, it is found that the coupling of plasma treated nanoparticles to silane coupling agent is significantly enhanced compared. The nanoparticles dispersion is much more homogeneous and the agglomeration has been effectively suppressed. Under bipolar continuous square impulse voltage, the Weibull lifetime is obviously prolonged, because of the interfacial layer modification by enhanced compatibility between nanoparticles and polymer matrices. Less space charge is detected, which can be interpreted by the trap level distribution results that the trap intensity and trap energy level are both slightly decrease. Shallower traps are beneficial to charge transfer in the nanocomposites, resulting in less space charge accumulation and longer lifetime.