Super-flexible, thermostable and superhydrophobic polyimide/silicone interpenetrating aerogels for conformal thermal insulating and strain sensing applications

Abstract

Soft and thermostable materials are crucial to applications in the fields of aerospace, wearable materials, and artificial intelligence (AI) in harsh environments. However, decided by the molecular structures, most soft materials are easy to pyrolyze at 100–200 °C, hindering developments in the critical technologies for such applications. In this work, through a rational “slice/sphere” dual-morphology microstructure design, a hydrogen-bonded polyimide/silicone aerogel is obtained with a two-step-gelling process. As rationally discussed with evidence, the recoverable “air compression” and the “silicone sphere deformation” contribute to the superflexibility, with the low elastic modulus (0.155 kPa), high cyclic compressive strain (90%), and good fatigue-resistance (600 cycles at 50% strain). Additionally, the structure and components together endow the composite with light weight (0.14–0.16 g cm−3), low bulk shrinkage (less than5%), superhydrophobicity (water contact angle of 150.1°), prominent thermostability (weight remains 90% at 474 °C), promising thermal insulating performance below 600 °C, and stable sensing ability at 300 °C. The efficient thermal insulation, sensible pizeopermittivity and endurance in a wide temperature window (−196–400 °C) make it feasible for conformal thermal protection and strain sensors for aerospace, and AI applications under harsh conditions.