Chemistry Department, Missouri University of Science and Technology, 400 W. 11th Street, Rolla, Missouri 65409, USA.
ACS Appl Mater Interfaces. 2013 Mar;5(6):1917-27. doi: 10.1021/am3030239. Epub 2013 Mar 14.
The interface between the polymer and the particle has a critical role in altering the properties of a composite dielectric. Polymer-ceramic nanocomposites are promising dielectric materials for many electronic and power devices, combining the high dielectric constant of ceramic particles with the high dielectric breakdown strength of a polymer. Self-assembled monolayers of electron rich or electron poor organophosphate coupling groups were applied to affect the filler-polymer interface and investigate the role of this interface on composite behavior. The interface has potential to influence dielectric properties, in particular the leakage and breakdown resistance. The composite films synthesized from the modified filler particles dispersed into an epoxy polymer matrix were analyzed by dielectric spectroscopy, breakdown strength, and leakage current measurements. The data indicate that significant reduction in leakage currents and dielectric losses and improvement in dielectric breakdown strengths resulted when electropositive phenyl, electron-withdrawing functional groups were located at the polymer-particle interface. At a 30 vol % particle concentration, dielectric composite films yielded a maximum energy density of ~8 J·cm(-3) for TiO2-epoxy nanocomposites and ~9.5 J·cm(-3) for BaTiO3-epoxy nanocomposites.
聚合物和颗粒之间的界面在改变复合材料介电性能方面起着关键作用。聚合物-陶瓷纳米复合材料是许多电子和电力设备有前途的介电材料，将陶瓷颗粒的高介电常数与聚合物的高介电击穿强度相结合。富电子或缺电子的有机磷酸酯偶联基团的自组装单层被应用于影响填充剂-聚合物界面，并研究该界面对复合材料性能的作用。该界面有可能影响介电性能，特别是漏电和击穿强度。通过介电光谱、击穿强度和漏电流测量分析了从改性填充颗粒分散到环氧树脂基体中合成的复合膜。数据表明，当正电荷的苯基、吸电子官能团位于聚合物-颗粒界面时，漏电流和介电损耗显著降低，介电击穿强度得到提高。在 30 体积%的颗粒浓度下，TiO2-环氧树脂纳米复合材料的最大能量密度约为 8 J·cm(-3)，BaTiO3-环氧树脂纳米复合材料的最大能量密度约为 9.5 J·cm(-3)。
