Mechanically robust and functional anisotropic conductive polymer composites with alternating microlayers

Anisotropic conductive polymer composites (ACPCs) are of great significance in electrical interconnection, miniaturized sensing devices and thermal management. The conductivity of ACPCs and conductivity ratio in different directions are the key to realize their applications. Actually, electrical properties are of significance, furthermore the mechanical properties of materials should attract more concern because conductive networks in ACPCs are commonly constructed by high volume of fillers with sacrificing mechanical properties of the final composites. Therefore, this study aims to improve significantly electrical properties of ACPCs while breaking limitation of the conductive fillers to damage the mechanical properties. In this work, ACPCs with alternative microlayers of biaxially oriented polypropylene (BOPP) and polypropylene (PP) filled carbon nanotubes (CNTs) are fabricated by low-temperature welding strategy. The electrical conductivity in X-direction reaches up to 10.1 S/m exhibiting a value 9.5 orders of magnitude higher than the value in Z-direction, while the products show super-high impact toughness of 12.3 kJ/m2 and tensile strength of 62.5 MPa, which is by far the most remarkable mechanical properties compared with the reported conductive PP-based composites. The integration of excellent electrical properties and high mechanical properties enables the materials to be applied to complex intelligent electronic device showing great applications value. Moreover, this ACPCs fabricating strategy is able to be scaled up due to simple, environmentally-friendly preparation process and low-cost raw materials, promoting ACPCs to be implemented in a variety of applications.