The breakdown strength and localised structure of polystyrene as a function of nanosilica fill-fraction

In this work the amorphous matrix of polystyrene provides a homogenous basis into which nanosilica particles are added. Composites are made with four different types of nanosilica particles which are subsequently compared. The DC breakdown strength of the resulting nanocomposite materials is measured as a function of filler fraction with loadings between 0 and 10 %. One advantage of using a polystyrene matrix for this study is its compatibility with permanganic etching. This technique is used to remove part of the polystyrene matrix and render the configuration of the nanofiller particles within the composite amenable to examination by scanning electron microscope (SEM). The simple sample preparation protocol employed here resulted in significant nanofiller agglomeration and the DC breakdown strength was found to decrease with increasing filler fraction.