Scalable and sustainable polymer conductivity enhancement through autonomous surface engineering

Developing polymer composites with high thermal and electrical conductivity often faces challenges due to heavy reliance on conductive fillers content or random transfer pathways. Herein, we propose a scalable, sustainable strategy to enhance conductivities by combining conductive filler-loaded semicrystalline polymer with immiscible amorphous polymer through a two-step melt processing. This approach hypothesizes for the first time that the filler preloaded phase encapsulates the amorphous polymer, increasing surface filler content and forming a pseudo-conductive surface. Using polyvinyl chloride and expanded graphite (25 vol%) preloaded high-density polyethylene as a “proof of concept” example, we have achieved in-plane thermal conductivity of 9.34 W·m⁻¹·K⁻¹ and in-plane bulk electrical conductivity of 117.92 S·m⁻¹, representing 84 % and 172 % increases over one-step composite. Melt flow behavior, surface studies, and computational simulations confirmed the pseudo-conductive surface's role. Our strategy is distinguished by its simplicity, cost-effectiveness, scalability, and versatility, offering a sustainable way to enhance electrical and thermal regulation in materials.