Shape Memory Polyimide Aerogel Fabrics with High‐Thermal‐Switching‐Ratio Enabled by Synergistic Micro‐ and Macro‐Deformation

ABSTRACT Intelligent thermal management textiles capable of adaptive thermal regulation represent an advanced solution for personal protective equipment, yet current systems face limitations in achieving simultaneous high thermal‐switching ratios and dynamic structural responsiveness. To address this challenge, we report a lightweight and flexible shape‐memory aerogel fabric based on polyimide‐block‐polysiloxane (PISi) that achieves a high thermal‐switching ratio through coordinated micro‐ and macro‐structural reorganization. The fabric exhibits reversible switching between a high‐thermal‐conductivity state (85.3 mW·m −1 ·K −1 ) with collapsed microscale pores and expanded inter‐fiber spacing, and a low‐thermal‐conductivity state (32.2 mW·m −1 ·K −1 ) with restored porosity and tight weaving—yielding a remarkable thermal switching ratio of 2.65. This bidirectional thermal regulation is driven by the shape‐memory‐induced synergy between the programmable macroscopic fabric geometry and the tunable porous microstructure of the aerogel fibers. Our work provides a transformative material design strategy toward next‐generation adaptive textiles with high thermal‐switching performance for intelligent thermal protection.