静电自组装铁电复合超薄膜及特性研究

将极化处理后充负电荷的聚偏氟乙烯（PVDF）有机铁电聚合物薄膜经溶解，与BaTiO₃无机纳米粉体形成良好分散的PVDF-BT荷电阴离子溶液和聚二丙烯基二甲基氯化铵（PDDA）聚阳离子溶液，通过静电作用在石英基片上交替自组装PDDA/PVDF-BT铁电复合超薄膜. 采用石英晶体微天平（QCM）、扫描电子显微镜（SEM）、X射线衍射分析（XRD）对该铁电复合超薄膜进行了表征. 研究结果表明：自组装12层PDDA/PVDF BT铁电复合超薄膜厚度为82nm，且静电自组装过程均匀，复合超薄膜表面平整、致密，无机纳米颗粒规整并均匀地覆盖在石英基底表面. 通过在PDDA/PVDF复合超薄膜间引入BaTiO₃无机纳米铁电粉体，可实现对超薄膜内部结构以及膜厚度的控制，极化强度可提高到约3μC/cm².

Preparation and Characterization of Ferroelectric Composite Ultrathin Film by Electrostatic Self-assembly

The ferroelectric ultrathin multilayer of PDDA/PVDF-BT were fabricated on the pretreated quartz substrates between cationic electrolyte of poly (diallyldimethyl ammonium chloride) (PDDA) and anion reagent by electrostatic self-assembly method. Negatively charged poly (vinylidene fluoride) (PVDF) dispersed with inorganic BaTiO₃ nano-granules in organic solvent was using as anion reagent. The thickness of the 12-layer ferroelectric composite ultrathin films characterized by quartz crystal microbalance (QCM) is about 82nm, and there exists a nearly linear relationship between the thickness and layer number of ultrathin films. The results of SEM and XRD show that the composite ultrathin films are deposited on the quartz surface smoothly and densely with uniform distribution of BaTiO₃ nano-granules, and excellent crystalline performance. The hysteresis loop of ferroelectric composite ultrathin films shows that the electric polarization of the composite ultrathin films is increased to 3μC/cm².