碳纤维/聚醚醚酮单向带各向异性导电行为的尺度效应

具有导电各向异性的高分子复合材料(ACPCs)在场发射装置及传感器设计领域具有重要应用。常规的ACPCs很难获得超大导电各向异性系数，且力学性能有限。本文采用碳纤维(CF)宽展、表面浸润与树脂复合一体化超薄热塑性单向带制备方法，制备厚度为0.04 mm和0.1 mm的CF增强聚醚醚酮(CF/PEEK)复合材料单向带，以PEEK纤维为纬线制备CF/PEEK复合材料单向编织布，采用热成型工艺制备CF/PEEK复合材料单向层合板。利用数字万用表和霍尔效应系统测试层合板面内及厚度方向的电阻率和面内的电子迁移率；采用超景深显微镜观察CF/PEEK复合材料单向层合板面内和厚度方向的纤维排列形貌。结果表明，超薄CF/PEEK复合材料单向层合板面内(纤维方向与横向)导电率之比高达377，而面内横向和厚度方向的导电率之比接近1，表明CF/PEEK复合材料获得了良好的横观各向同性；超薄化CF/PEEK复合材料的面内电子迁移行为同样具有巨大的各向异性，这一结果为CF/PEEK复合材料在场发射器件、传感器设计及其灵敏度调控方面提供了实验基础。 

Thickness effect of anisotropic conductive behavior of carbon fiber/polyetheretherketone unidirectional tape

The conductive anisotropic polymer composites(ACPC)have important applications like field emission devices and electronic sensors.Conventional ACPC are difficult to obtain large conductive anisotropy coefficients and present limited mechanical properties.In this paper,novel technology integrated carbon fiber(CF)spread,surface modification with stacking thermoplastic film was used to prepare CF reinforced polyetheretherketone(CF/PEEK)composite unidirectional tape with thicknesses of 0.04 mm and 0.1 mm.CF/PEEK composite unidirectional woven cloth was prepared with PEEK fiber was used as a binder weft,and CF/PEEK composite unidirectional laminate was prepared by thermoforming process.The in-plane and the thickness directional resistivities of unidirectional laminate were measured by digital multimeter and in-plane electron mobility was tested by Hall effect system.The fiber arrangement within in-planes along the fiber direction and the thickness direction of CF/PEEK composite unidirectional laminate were observed with an ultra-depth microscope.The results show that the inplane(fiber direction to transverse direction)conductivity ratio of ultra-thin CF/PEEK composite unidirectional laminate reaches to 377,while conductive ratio in the transverse direction to the thickness direction is close to 1,indicating that thin CF/PEEK composite unidirectional laminate presents transverse isotropic electric performance.The results of electron migration also indicate in-plane huge anisotropic conductivity.The results are important for CF/PEEK composite to be used in field emission devices and electronic sensors.