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

Abstract

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 in-plane (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.