Optimizing Strategy for the Dielectric Performance of Topological-structured Polymer Nanocomposites by Rationally Tailoring the Spatial Distribution of Nanofillers

There is a mindset that functional fillers tend to be as homogeneous as possible to achieve high dielectric constant and low loss when designing polymer dielectric composites. This study breaks the mindset by proposing a novel inhomogenous design in a topological-structured polymer nanocomposite, the dielectric performance is optimized by rationally controlling the spatial distribution of nanofillers. We prepared layered composites where BaTiO3 and TiN nanoparticles were dispersed in the top and bottom section of the poly(vinylidene difluoride-co-hexafluoropropylene) (P(VDF-HFP)) composites, respectively. Interestingly, the layered inhomogenous composites exhibit obviously enhanced dielectric permittivity (1.5 times as high), suppressed loss (a 70 % drop) and improved breakdown strengths (4.2 times as high) compared with their single-layer homogenous counterparts. This dielectric optimization is mainly attributed to the design of multilevel interfaces and the redistribution of polarization charges in the inhomogenous topological structure. This research provides a novel optimizing strategy and will promote the development of dielectrics.