Abstract
Polymer nanocomposites (PNC) have attracted enormous scientific and technological interest due to their applications in energy storage, electronics, biosensing, drug delivery, cosmetics and packaging industry. Nanomaterials (platelet, fibers, spheroids, whiskers, rods) dispersed in different types of polymer matrices constitute such PNC. The degree of dispersion of the inorganic nanomaterials in the polymer matrix, as well as the structured arrangement of the nanomaterials, are some of the key factors influencing the overall performance of the nanocomposite. To this end, the surface functionalization of the nanomaterials determines its state of dispersion within the polymer matrix. For energy storage and electronics, these nanomaterials are usually chosen for their dielectric properties for enhancing the performance of device applications. Although several reviews on surface modification of nanomaterials have been reported, a review on the surface functionalization of nanomaterials as it pertains to polymer dielectrics is currently lacking. This review summarizes the recent developments in the surface modification of important metal oxide dielectric nanomaterials including Silicon dioxide (SiO2), titanium dioxide (TiO2), barium titanate (BaTiO3), and aluminum oxide (Al2O3) by chemical agents such as silanes, phosphonic acids, and dopamine. We report the impact of chemical modification of the nanomaterial on the dielectric performance (dielectric constant, breakdown strength, and energy density) of the nanocomposite. Aside from bringing novice and experts up to speed in the area of polymer dielectric nanocomposites, this review will serve as an intellectual resource in the selection of appropriate chemical agents for functionalizing nanomaterials for use in specific polymer matrix so as to potentially tune the final performance of nanocomposite.