Enhanced dielectric properties of polyvinylidene fluoride nanocomposites via calcium copper titanate nanofibers

Abstract

Polymer matrix nanocomposites with high permittivity attract more and more attention due to their flexibility, easy processing, low cost and wide applications of electronic industry. However, the permittivity of the majority of polymers are quite low. The most effective method is combining polymers and high-permittivity inorganic ceramics (such as TiO2, barium titanate, lead zirconate titanate and etc.). Calcium copper titanate (CCTO) is a promising candidate for fabrication high dielectric constant composites owing to its giant (>105) and stable permittivity over a very wide temperature range from 100 K to 500 K. In this research, the one-dimensional CCTO nanofibers (CCTO-NFs) with high aspect ratio were prepared by a novel strategy combining sol-gel method and electrospinning technology. The diameter of CCTO nanofibers is less than 300 nm. The morphology of CCTO nanofibers was researched by thermogravimetry-differential thermal analysis (TG-DTA) and scanning electron microscope (SEM). Based on the CCTO nanofibers, a novel composite with polyvinylidene fluoride (PVDF) matrix was prepared via the solution casting method. The permittivity of CCTO-NFs/PVDF composites was measured depending on different fillers loading. The results showed that CCTO nanofibers can improve the dielectric property of the PVDF composites effectively and the permittivity of composites increased with the increasing CCTO nanofibers loading. The PVDF nanocomposite with a low loading (7 vol%) exhibits good dielectric property. In addition, the permittivity of 22, which is about 2.4 times of neat PVDF, was obtained with 20 vol% loading of CCTO nanofibers/PVDF composite. This work indicates that CCTO nanofibers are potential fillers to develop the dielectric property of polymer composites and provide a new possibility to fabricate high-permittivity polymer nanocomposites.