Measuring the Permittivity of Barium Titanate Nanoparticles in an Epoxy Composite*

Barium titanate (BTO) is used as a dielectric material due to its high dielectric constant, which ranges from 1500 to 2000 in bulk [1]. Literature remains unclear on how BTO nanoparticle size impacts the dielectric constant, particularly for non-sintered, discrete nanoparticles. Studies have reported nanoparticle dielectric constants ranging from 135 [2] to 5000 [3].

We developed a procedure for fabricating BTO-epoxy nanocomposite materials, using ball-milling steps alongside surfactants to reduce nanoparticle agglomeration. We compare observed composite dielectric constants to finite-element models at various levels of agglomeration to determine the nanoparticle dielectric constant for nanoparticles with diameters between 50 and 500 nm.

[1] Arlt et al. Journal of Applied Physics 58 (1985): 1619.
[2] Siddabattuni et al. Journal of the American Ceramic Society 96.5 (2013): 1490.
[3] Wada et al. Japanese Journal of Applied Physics 42 Part 1, No. 9B (2003): 6188.