Asymmetric Gradient Porous Fabric with Dynamically Tunable Thermal Management and Electromagnetic Interference Shielding via Delayed Phase Separation

Abstract

The rapid development of global urbanization has exacerbated the urban heat island effect and electromagnetic radiation pollution. However, existing fabrics fail to provide both effective personal thermal management and electromagnetic interference (EMI) shielding. To address this challenge, an asymmetric gradient porous fabric (AGPF) is developed using a delayed evaporation-induced phase separation strategy. The AGPF consists of gradient porous polystyrene-block-poly(ethylene-ran-butylene)-block-polystyrene (SEBS) and transversely oriented liquid metal (LM) networks with wrinkled structures at the bottom. Due to the complete sedimentation of liquid metal, the gradient porous SEBS maintains excellent solar reflectivity of 93.9% and atmospheric window infrared emissivity of 94.7%. Upon activation by pre-stretching, LM imparts AGPF high electrical conductivity and enhanced stretchability to the AGPF, resulting in excellent EMI shielding effectiveness of 80.6 dB and electrical heating performance. Outdoor cooling tests further confirmed that AGPF achieves sub-ambient cooling of ≈9.5 °C. Moreover, AGPF exhibits dynamically tunable thermal management and EMI shielding performance across a strain range of 0% to 200%, adapting to complex outdoor environments. The design of AGPF provides an advanced solution to protect individuals from the dual threats posed by urban heat island effects and electromagnetic pollution.