Application of cold plasma in nanofillers surface modification for enhancement of insulation characteristics of polymer nanocomposites: A review

Polymer nanocomposites have gained much attention among researchers due to their excellent characteristics, such as high thermal resistivity and the ability to withstand higher electrical stress. Introducing nanoparticles into the polymer matrix can further improve the insulation characteristics. However, the effectiveness of polymer nanocomposite to suppress an electrical tree, enhancing the partial discharge, and increase the breakdown strength is still a question mark due to the agglomeration issue of nanoparticles, which causing the nanoparticle to be dispersed non-uniformly within the polymer matrix. Plasma treatment is one of the methods that potentially replace conventional modification techniques such as chemical functionalization and heat treatment to improve the dispersion of nanoparticles, nanocomposite bonding, and the compatibility between polymer-nanoparticle interfaces. By altering the surface of nanoparticles using cold plasma with a glow discharge mechanism, the surface morphology of nanoparticles can be modified in terms of chemical structure, which indirectly solves the nanoparticle agglomeration. This study presents a review on the application of cold plasma in surface modification to enhance insulation characteristics of polymers nanocomposite. Various polymer hosts combined with different untreated and plasma-treated nanofillers are also reviewed. The trends on nanomaterial surface modification using the cold plasma technique based on its operating pressure to improve the dielectric properties of polymers nanocomposite are also discussed accordingly