Core–Shell Approach to Control Acid–Base Properties of Surface of Dielectric and Permittivity of Its Composite

Hybrid organic–inorganic composites comprising cyanoethyl ester of poly(vinyl alcohol) (CEPVA) and submicron-sized barium titanate with a core–shell structure are studied. For the first time, the permittivity of obtained composites was studied in correlation with the acid–base properties of the filler and controlled via the filler surface modification by the formation of core–shell structures using sol–gel and plasma processes. The permittivity is found to grow with the increase in the content of Brønsted basic centers on the filler surface due to enhanced interactions with acid groups of polymer. This effect is especially prominent in the case of silica nanocoating deposited onto BaTiO3 surface. The permittivity of the studied composites is approximated by a modified Lichtenecker equation based on permittivity values of individual components, their concentrations, and a specific parameter characterizing their acid–base interaction.