Au@PS纳米颗粒掺杂PDMS/(PVDF-TrFE)复合薄膜的制备及介电-疏水性能

结合乳液聚合和还原法在250 nm的聚苯乙烯(PS)微球表面均匀负载了Au纳米颗粒. 通过溶液共混法, 使Au@PS纳米颗粒与聚二甲基硅氧烷(PDMS)/聚偏氟乙烯-三氟乙烯P(VDF-TrFE)](质量比为2∶3)均匀混合, 制备出结构致密、 Au@PS均匀分布的微突起的复合薄膜. 研究了不同Au@PS纳米颗粒掺杂量对复合薄膜的结构、 熔融结晶行为和介电疏水特性的影响. 研究发现, Au@PS纳米颗粒的引入阻碍了P(VDF-TrFE)的β相的产生, 但对PDMS/P(VDF-TrFE)复合薄膜的化学健结构没有显著影响; 随着Au@PS纳米颗粒含量的增多, 复合薄膜结晶温度和玻璃化转化温度升高, 熔点略有降低. 由于界面极化和微电容效应协同作用, 掺杂Au@PS复合薄膜的介电常数有显著提升. PS球表面均匀负载的Au纳米颗粒减少了导电网络的构成, 使介电损耗维持在较低值. 掺杂5%(质量分数)Au@PS的复合薄膜介电常数达到22(100 Hz), 分别为纯PDMS和PDMS/P(VDF-TrFE)的8.8倍和3.14倍, 同时具有优异的疏水特性, 接触角达到112.31°.

Preparation and Enhanced Dielectric-hydrophobic Properties of PDMS-PVDF Composite Films with Au@PS Nanoparticle †

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.