Flexible, breathable, and reinforced ultra-thin Cu/PLLA porous-fibrous membranes for thermal management and electromagnetic interference shielding

Electromagnetic interference shielding and thermal management by wearable devices show great potential in emerging digital healthcare. Conventional metal films implementing the functions must sacrifice either flexibility or permeability, which is far from optimal in practical applications. In this work, an ultra-thin (15 µm), flexible, and porous Cu/PLLA fibrous membrane is developed by depositing copper particles on the polymer substrate. With novel acetone & heat treatment procedure, the membrane is considerably stronger while maintaining the porous fibre structure. Its fantastic breathability and super high electrical conductivity (9471.8130 S/cm) enable the composites to have fast electrical heating characteristics and excellent thermal conductivity for effective thermal management. Meanwhile, the porous polymer substrate structure greatly enhances the diffusion of conductive substances and increases the electromagnetic interference shielding effectiveness of the membranes (7797.98 dB cm2/g at the H band and 8072.73 dB cm2/g at the Ku band respectively). The composites present high flexibility, breathability, and strength with the functions of thermal management and electromagnetic shielding, showing great potential for future portable electronic devices and wearable integrated garments.