Large-scale fabrication and electrical properties of an anisotropic conductive polymer composite utilizing preferable location of carbon nanotubes in a polymer blend

An anisotropically conductive polymer composite (ACPC) based on carbon nanotubes (CNTs) and polycarbonate (PC)/polyethylene (PE) blend was fabricated via a slit die extrusion-hot stretch process. Under the influence of the shear flow and hot stretch, the PC phase is in situ deformed into aligned conductive fibrils in the PE matrix, whose surface region holds the majority of CNTs. When the stretch ratio rises to a certain level, the resistivity of the ACPC shows a strong anisotropy of three orders of magnitude difference between the perpendicular and parallel stretch directions. The fibrillar ACPC shows a weak positive temperature coefficient (PTC) effect, and two-process negative temperature coefficient (NTC) effect caused by the reorganization of PC fibrils below but near 230 °C, and the transformation from anisotropy to isotropy beyond 230 °C. The obtained ACPC allows it to have such potential applications as switch and sensor materials.