Multifunctional Polyimide/Carbon Nanofiber Composite Aerogels for Electromagnetic Interference Shielding, Thermal Insulation, and Joule Heating

Abstract

The rapid development of electronic devices has increased demand for lightweight, multifunctional shielding materials. In this work, a polyimide-based composite aerogel incorporating oxygen-functionalized/acidified carbon nanofibers (CNFs) was successfully fabricated via freeze-drying followed by thermal imidization. The obtained composite aerogels exhibited effective EMI shielding effectiveness of 56.6 dB in the X-band region. The aerogel exhibited a green index (GI) value greater than 1 for all composite samples, indicating that absorption is the dominant shielding mechanism, and it also exhibited high elastic recovery and mechanical resilience. The composite aerogel also showed excellent thermal insulation, with a thermal conductivity of 0.06 W·m–1·K–1, as well as flame resistance and thermal stability. Furthermore, the composite aerogels exhibit efficient Joule heating behavior, attaining a temperature of 173 °C under an applied voltage of 8 V, with rapid and stable temperature response. This work provides a multifunctional composite aerogel with its potential applications in aerospace, defense sectors and electronic devices for advanced EMI shielding and thermal management.