Directional freeze wet-spun polyimide aerogel fabric loaded with MXene/Liquid metal coating for infrared stealth and motion sense

Composite aerogel fabric with integrated infrared stealth and strain-sensing functionalities was fabricated by a highly porous Polyimide (PI) aerogel substrate via directional freeze-assisted wet spinning combined with an ice-templating method. After interfacial modification with polydopamine on the weaved aerogel fabric, MXene and gallium-indium-tin liquid metal (LM) were ultrasonically emulsified and then loaded on the aerogel fabric under ice-water bath conditions. Characterization results show that the porous PI substrate exhibits a low thermal conductivity of 0.03546 W m⁻¹ K⁻¹, and the composite fabric achieves an infrared emissivity as low as 0.298. Leveraging the synergistic effect of thermal insulation from the substrate and low radiation from the conductive layer, the fabric enables stable infrared camouflage in the temperature range of 50-100 °C. COMSOL simulation of heat transfer in PIMLM fabric confirms the passive cooling effect effectively lowers the thermodynamic temperature of the fabric surface, providing crucial support for its wide-temperature-range infrared stealth capability. In sensing tests, the sample demonstrates a response time of 122 ms and a recovery time of 328 ms, along with excellent signal reproducibility under multilevel strain and various tensile rates, enabling real-time monitoring of human limb movements. This fabrication approach provides a feasible strategy for the development of multifunctional wearable stealth sensing fabrics.