Humidity‐Triggered Spontaneous Phase Separation Enables Multifunctional 3D Porous Composites for Piezoresistive Mechanosensory and Electromagnetic Interference Shielding

ABSTRACT Three‐dimensional (3D) porous composites have attracted significant attention for piezoresistive sensing and electromagnetic interference (EMI) shielding applications owing to their large specific surface area, excellent electrical conductivity, and remarkable flexibility. However, the fabrication of these composites with minimal complexity and equipment requirements remains challenging. Here, we present a facile humidity‐triggered nonsolvent vapor‐induced phase separation (NVIPS) approach to fabricate 3D porous composites using a thermoplastic polyurethane solution on reduced graphene oxide‐modified carbon fiber felt under ambient conditions. The fabricated composites exhibit exceptional piezoresistive stability with rapid response (60 ms), a broad pressure detection range, high air permeability (358 mm s −1 ), and outstanding X‐band EMI shielding (74 dB). Moreover, by integrating a neural network model, an intelligent cognition system capable of real‐time recognition of the object material species is constructed via robotic touch under varying pressures (accuracy > 97.8%). Our bioinspired NVIPS strategy offers a versatile solution for multifunctional sensing and EMI protection through the highly flexible, breathable, and conductive porous composites.