Graphene sheets segregated by barium titanate for polyvinylidene fluoride composites with high dielectric constant and ultralow loss tangent
Graphene sheets segregated by barium titanate for polyvinylidene fluoride composites with high dielectric constant and ultralow loss tangent
复制标题
钛酸钡偏析石墨烯片用于高介电常数和超低损耗角正切聚偏二氟乙烯复合材料
DOI：
10.1016/j.compositesa.2015.08.031
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发表时间：
2015-11-01
影响因子：
8.7
通讯作者：
Fu, Qiang
中科院分区：
文献类型：
--
作者：
Li, Yuhan;Shi, Yunjie;Fu, Qiang
在本文中，我们报告了一种独特的方法来开发聚偏氟乙烯（PVDF）复合材料具有高介电常数和低损耗角正切加载相对较低的含量的石墨烯封装的钛酸钡（BT）杂化填料。通过静电自组装和化学还原制备了氧化石墨烯包覆的BT颗粒（BT-GO）。SEM形貌显示RGO片被BT颗粒隔离。杂化填料具有两个优点，用于调谐介电性能：负载极低含量的RGO可以精确控制，并且由BT颗粒隔离的单个RGO片可以防止漏电流。结果表明，BT-RGO填充的PVDF复合材料在发生介电行为之前表现出更好的介电性能。填充有30体积% BT-RGO的复合材料分别具有67.5和0.060（1 kHz）的介电常数和损耗角正切（tan δ）值。相比之下，填充有30体积% BT-GO和BT的复合材料的介电常数和tan δ分别为57.7和38.3、0.076和0.042（1 kHz）。介电常数的改善归因于由BT颗粒隔离的高导电RGO片形成的微电容器。同时，相邻RGO片之间的距离足够大，以防止漏电流的隧穿电导，其中tan δ显着约束。结果表明，该方法可作为减少陶瓷填料用量的指导。(C)2015爱思唯尔有限公司出版
In this paper, we report a unique method to develop polyvinylidene fluoride (PVDF) composites with high dielectric constant and low loss tangent by loading relatively low content of graphene-encapsulated barium titanate (BT) hybrid fillers. BT particles encapsulated with graphene oxide (BT-GO) were prepared via electrostatic self-assembly and subsequent chemical reduction resulted in BT-RGO particles. SEM morphology revealed that RGO sheets were segregated by BT particles. The hybrid fillers have two advantages for tuning dielectric properties: loading extremely low content of RGO can be exactly controlled and individual RGO sheets segregated by BT particles would prevent leakage current. As a result, PVDF composites filled with BT-RGO displayed improved dielectric properties before percolative behavior occurred. Composites filled with 30 vol% BT-RGO have a dielectric constant and loss tangent (tan delta) value of 67.5 and 0.060 (1 kHz), respectively. By contrast, dielectric constant and tan delta of composites filled with 30 vol% BT-GO and BT were 57.7 and 38.3, 0.076 and 0.042 (1 kHz), respectively. The improvement of dielectric constant is attributable to the formation of microcapacitors by highly conductive RGO sheets segregated by BT particles. Meanwhile, the distance between adjacent RGO sheets is large enough to prevent leakage current from tunneling conductance, by which tan delta is remarkably constrained. The composites could achieve excellent dielectric properties by loading relatively low amount of ceramic fillers, which indicates that this method can be used as guideline for reduce the usage amount of ceramic fillers. (C) 2015 Published by Elsevier Ltd.