Low dielectric constant of polymer based composites induced by the restricted polarizability in the interface

Abstract Polyimide (PI) based composites filled by modified-TiO2 particles were fabricated by in-situ dispersive polymerization. The results show that there are lots of interface regions between organic-inorganic. With TiO2 content increasing, the dielectric constant of the composites firstly varies from 3.35 to 3.16 (0–3 wt%), then increases to 3.46 (3–7 wt%) at 0.1 Hz. The restricted orientation and electronic distortion polarizabilities in the interface are responsible for the reduced dielectric constant. The restricted effect along with the enhanced interfacial polarization determines the variation of dielectric constant of PI/TiO2 composites. The present work provides a promising route to the design and fabrication of low-K polymer composites.