3D segregated architecture BaTiO_3/polystyrene composites with enhanced dielectric constant fabricated via hot pressing core-shell polystyrene@BaTiO_3 composite microspheres

摘要

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 BaTiO_3 (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.