Fabrication of barium titanate nanoparticles-epoxy resin composite films and their dielectric properties

A method for fabricating epoxy resin films dispersing the surface-modified barium titanate (BT) particles (BTepoxy resin composite films) are proposed. BT particles with a size of 7.8 nm and a crystal size of 8.6 nm were synthesized with a complex alkoxide method. To introduce epoxy groups on the BT particle surface, the BT particles were surface-modified with 2-(3,4-epoxycyclohexyl)- ethyltrimethoxysilane. A precursor solution, which was prepared by prereacting 2,2-bis(4-glycidyloxyphenyl) propane (BGPP) and phthalic anhydride in 4-butyrolactone and adding the surface-modified BT particles to the prereacting solution, was spin-coated on glass substrates to fabricate the composite films. An increase in BT volume fraction in film increased dielectric constant of the composite film while keeping dissipation factor below 0.03. The dielectric constant attained 10.8 at a BT volume fraction of 30% in film that was around twice higher than pure epoxy resin film.