Effect of shell phase composition on the dielectric property and energy density of core-shell structured BaTiO3 particles modified poly(vinylidene fluoride) nanocomposites

Dielectric nanocomposites have attracted much attention due to their wide applications in electronics and electrical industry. Recently, incorporating core-shell nanoparticles into polymer matrix to improve the dielectric properties of nanocomposites has been widely reported. Tailoring the interfacial region between the polymer and the nanoparticles plays a crucial role in achieving the desired dielectric and energy storage properties of nanocomposites. However, the effect of shell structure in the interface region on the dielectric and energy storage properties is rarely studied. Based on this, core-shell BaTiO 3 nanoparticles with two different shell polymers, a “hard-soft” copolymer of methyl methacrylate and butyl acrylate (P[MMA-BA]) and a “hard” homopolymer of methyl methacrylate (PMMA), were prepared in this paper. The effect of core-shell BaTiO 3 nanoparticles with different shell structures on the dielectric and energy storage properties of poly(vinylidene fluoride) (PVDF) was investigated in depth. Due to the formation of a tight interfacial region between P(MMA-BA)@BT and PVDF matrix, P(MMA-BA)@BT/PVDF nanocomposites not only have low dielectric loss but also higher energy efficiency than PMMA@BT/PVDF nanocomposites. This study suggests a potential strategy that fabricating a “hard-soft” copolymer shell on BaTiO 3 surface can obtain desirable energy storage efficiency than the single “hard” shell structure in dielectric nanocomposites.