High-k dielectric composites of poly(2-cyanoethyl vinyl ether) and barium titanate for flexible electronics

High-k dielectric composite material for electronic applications was obtained by mixing a polymer with high dielectric constant, poly(2-cyanoethyl vinyl ether) (CEPVA), and highly crystalline barium titanate (BT). Barium titanate nanoparticles of a size in the range 40–90 nm were prepared by the solvothermal method. By optimizing the reaction conditions, the formation of carbonate impurities and the agglomeration of formed nanoparticles were significantly reduced compared to state-of-the-art procedures. Dielectric spectroscopy was measured in the range of 0.01 Hz to 10 MHz and showed the dielectric constant to be ɛ′ ∼ 35–40 with only 30 vol % content of BT in the composite. Extrapolating to 100% BT nanoparticle concentration and using the Lichtenecker model, the dielectric constant ɛ′ = 365 ± 27 at 10 kHz was obtained. The relaxation and electrical properties were investigated in depth, and a new relaxation phenomenon was revealed. CEPVA/BT composite is considered suitable for electronic applications, in which high ɛ′ together with a good mechanical flexibility are required, such as organic field effect transistors. © 2017 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017, 134, 45236.