Investigating the Dielectric Constant of Functionalized Barium Titanate Within a Polymer Nanocomposite

Barium Titanate (BTO) is a ferroelectric perovskite material that is widely studied and commonly used in state-of-the-art capacitors due to its high dielectric permittivity [1] [2] [3]. This value is generally understood to be ~5000 [2]. However, it has been reported that BTO exhibits a sharp increase in dielectric constant to over 15000 at a particle size of 70 nm [5], which is intriguing yet highly contested. Here we present an investigation of the dielectric constant of BTO across six particle sizes ranging between 50 nm and 500 nm. Dielectric constants of BTO nanoparticles were determined by incorporating surface-functionalized BTO into an ABS polymer matrix at high volume loadings with low levels of agglomeration. Nanocomposite pellets were then injection-molded into disc shapes and sputtered with gold to fabricate a dielectric parallel plate capacitor. The dielectric constant was then extracted from capacitance measurements and cross-validated with computational values obtained from a COMSOL finite element model of the nanocomposite. As the global search for improved systems of energy storage and power conditioning hastens, these results may prove valuable in the development of solutions that power the future.<br/>Sandia National Laboratories is a multimission laboratory managed and operated by National Technology and Engineering Solutions of Sandia, LLC., a wholly owned subsidiary of Honeywell International, Inc., for the U.S. Department of Energy’s National Nuclear Security Administration under contract DE-NA0003525.<br/>[1] Fan, H., Wei, R., Guanghua, L., Peng, S., Xiaoqing, W., Xiaofeng, C., “Structure and dielectric properties of barium titanate thin films for capacitor applications.” Ceramics International, 39 (2013).<br/>[2] Arlt, G., Hennings, D., de With, G., “Dielectric properties of fine-grained barium titanate ceramic capacitors.” Journal of Applied Physics, 58 (1985).<br/>[3] Briscoe, J., Dunn, S., “Piezoelectricity and Ferroelectricity. Nanostructured Piezoelectric Energy Harvesters”. SpringerBriefs in Materials (2014).<br/>[4] Wada, S., Yasuno, H., Hoshina, T., Nam, S-M., Kakemoto, H., Tsurumi, T., “Preparation of nm-Sized Barium Titanate Fine Particles and Their Powder Dielectric Properties.” Japanese Journal of Applied Physics (2003).