Abstract:

Au nanoparticles were uniformly loaded on the surface of polystyrene(PS) microspheres with an average diameter about 250 nm via the emulsion polymerization and reduction method. The PS/Au was homogeneously mixed with polydimethylsiloxane(PDMS)/poly(vinylidene fluoride-co-trifluoroethylene)[P(VDF-TrFE)](mass ratio: 2∶3) by solution blending method, and the dense composite film with uniform distribution of Au@PS particle and micro bulge surface were obtained. The effects of Au@PS doping content on composite films structure, melting crystallization behavior and dielectric-hydrophobic properties were investigated. It was found that the introduction of Au@PS nanoparticles hinders the β phase formation of P(VDF-TrFE), but has no obvious effect on the bonding structures. The crystallization temperature and glass-transition temperature of composite films increases, and their melting point decreases slightly with increasing the Au@PS content. Due to the synergistic effect of interface polarization and micro capacitance, the dielectric constant of composite film with Au@PS nanoparticles is significantly increased. The Au nanoparticles uniformly loaded on the surface of PS sphere reduce the formation of conductive network, thus maintain a relatively low dielectric loss value. Typically, the dielectric constant of the blend film with 5%(mass fraction) Au@PS nanoparticle reaches 22 at 100 Hz, which is 8.8 and 3.14 times that of pure PDMS and PDMS/P(VDF-TrFE), respectively. The blend film with 5%Au@PS also possesses a large contact angle of 112.31° due to the interaction of hydrophilic Au nanoparticles and the existence of micro bulge structure. All the improved performances show great potential application for electrowetting devices.

Key words: Solution method, Dielectric property, Hydrophobic performance, Composite film