3D segregated architecture BaTiO3/polystyrene composites with enhanced dielectric constant fabricated via hot pressing core–shell polystyrene@BaTiO3 composite microspheres

Abstract

How to obtain high dielectric constant using low filler content is one of the urgent problems to be solved in the research field of ceramic/polymer dielectric materials. In traditional methods (fillers are randomly distributed), filler particles are isolated by thick layers of polymers (with low dielectric constant), which usually result in ultra-low enhancement efficiencies of dielectric constant for the composites. To solve the above puzzle, this study provides a new strategy to improve the dielectric constant of ceramic/polymer composites, that is constructing 3D segregated architectures of BaTiO3 (BT networks) in polystyrene (PS) matrix. This strategy is expected to enhance dielectric interaction between BT particles and greatly improve the dielectric constant of BT/PS composites. In this method, PS@BT core–shell microspheres were firstly fabricated by electrostatic self-assembling the BT particles on PS microspheres. BT/PS composites with BT networks were constructed by hot pressing above core–shell microspheres. Microstructures of PS@BT microspheres and BT/PS composites were investigated. Dielectric properties of BT/PS composites with various BT contents were studied. Results show that dielectric constant of the BT/PS composites is up to 41.8 when BT content is only 30vol%, which is much higher than that of traditional composites. This research provides us a facile method to design and fabricate ceramic/polymer composites with high dielectric constant and low loss.