Flexible polyimide-based conductive composite film with confined carbon nanotubes networks for EMI shielding and joule heating

Electromagnetic interference (EMI) poses a growing challenge for wearable electronics, wireless communication and aerospace systems, driving the need for shielding materials that are lightweight, flexible and durable under extreme conditions. We developed polyimide (PI)/carbon nanotube (CNT) composite films through solution casting and thermal imidization. The thermal stability, chemical resistance and mechanical strength of PI, together with the high conductivity of CNTs, created dense and uniform conductive networks in the polymer. The optimized PI/CNT-7:3 films achieved conductivity of 1.96 × 10 3 S m -1 and EMI shielding effectiveness of 39.7 dB in the X-band. The composites retained strong shielding at −196 °C and 150 °C, in corrosive NaCl/HCl solutions and after 500 bending cycles, with efficiency loss below 1.53%. They also provided rapid and stable Joule heating at low voltages (<6 V), reaching 142 °C within seconds and enabling efficient electrothermal de-icing. With high EMI shielding, environmental durability, flexibility and multifunctional electrothermal capability, PI/CNT films should offer a robust platform for next-generation wearable electronics, aerospace communication, defense technologies and thermal management devices.