Gao Xiaolong, Huang Yao, He Xiaoxiang, Fan Xiaojing, Liu Ying, Xu Hong, Wu Daming, Wan Chaoying
College of Mechanical and Electrical Engineering, Beijing University of Chemical Technology, Beijing 100029, China.
State Key Laboratory of Organic-Inorganic Composites, Beijing University of Chemical Technology, Beijing 100029, China.
Polymers (Basel). 2019 Jan 2;11(1):56. doi: 10.3390/polym11010056.
Electrically conductive polymer composites are in high demand for modern technologies, however, the intrinsic brittleness of conducting conjugated polymers and the moderate electrical conductivity of engineering polymer/carbon composites have highly constrained their applications. In this work, super high electrical conductive polymer composites were produced by a novel hot embossing design. The polydimethylsiloxane (PDMS) composites containing short carbon fiber (SCF) exhibited an electrical percolation threshold at 0.45 wt % and reached a saturated electrical conductivity of 49 S/m at 8 wt % of SCF. When reducing the sample thickness from 1.0 to 0.1 mm by the hot embossing process, a compression-induced percolation threshold occurred at 0.3 wt %, while the electrical conductivity was further enhanced to 378 S/m at 8 wt % SCF. Furthermore, the addition of a second nanofiller of 1 wt %, such as carbon nanotube or conducting carbon black, further increased the electrical conductivity of the PDMS/SCF (8 wt %) composites to 909 S/m and 657 S/m, respectively. The synergy of the densified conducting filler network by the mechanical compression and the hierarchical micro-/nano-scale filler approach has realized super high electrically conductive, yet mechanically flexible, polymer composites for modern flexible electronics applications.
导电聚合物复合材料在现代技术中需求很高，然而，导电共轭聚合物固有的脆性以及工程聚合物/碳复合材料适度的电导率极大地限制了它们的应用。在这项工作中，通过一种新颖的热压花设计制备了超高导电聚合物复合材料。含有短碳纤维（SCF）的聚二甲基硅氧烷（PDMS）复合材料在0.45 wt%时表现出渗流阈值，在8 wt%的SCF时达到49 S/m的饱和电导率。通过热压花工艺将样品厚度从1.0 mm减小到0.1 mm时，在0.3 wt%出现压缩诱导渗流阈值，而在8 wt%的SCF时电导率进一步提高到378 S/m。此外，添加1 wt%的第二种纳米填料，如碳纳米管或导电炭黑，分别将PDMS/SCF（8 wt%）复合材料的电导率进一步提高到909 S/m和657 S/m。通过机械压缩使导电填料网络致密化以及采用分级微/纳米尺度填料方法的协同作用，实现了用于现代柔性电子应用的超高导电且机械柔性的聚合物复合材料。
