Preparation and dielectric properties of core-shell structural composites of poly(1H,1H,2H,2H-perfluorooctyl methacrylate)@BaTiO_3 nanoparticles

摘要

Polymer nanocomposite films, poly(1H,1H,2H,2H-perfluorooctyl methacrylate)@BaTiO_3 (PPFOMAOBaTiO_3), with enhanced dielectric permittivity was fabricated via a two-step processes, consisting of BaTiO_3 nanoparticle surface modification and surface initiated atom transfer radical grafting polymerization (SI-ATRP). At first, BaTiO_3 nanoparticles were treated by hydroxylation, silylation and amidation to offer their Sl-ATRP capability. Then PPFOMA chains were grafted from the modified BaTiO_3 nanoparticles by SI-ATRP at 70 ℃ to form core-shell composites. The effects of polymer structure and polymer/BaTiO3 ratios on dielectric properties were measured over a broad frequency from 40 Hz to 30 MHz at room temperature. The results showed that the dielectric constant (k) increased and dielectric loss reduced significantly with the addition of BaTiO_3. The k of the composite was up to 7.4 at 100 kHz at room temperature when the BaTiO_3 loading was up to 70.70 wt% which is almost three time of pure PPFOMA (k = 2.6). While the dielectric loss (tanδ) of PPFOMA@BaTiO_3 composite was about 0.01, which was much lower than that of the pure PPFOMA (tan δ = 0.04).