Closed‐Pore Engineering in Double‐Layer Textiles for Adaptive Thermal and Moisture Management

Protective textiles face a critical challenge in cold and moisture-rich environments, in which conventional layered clothing systems and multi-layer functional textiles often sacrifice breathability and comfort to enhance insulation, or conversely, lose body heat with moisture accumulation. Here, back-weft weaving technology is combined with an in situ foaming process to produce an interlocking double-layer textile (Foam-TEX) featuring abundant closed-pore microspheres on the foamed fibers and gradient pores throughout the textile. The closed-pore structural engineering spatially couples the closed-pore insulation unit with the gradient vapor transmission channel to ensure thermal comfort in cold environments, while effectively preventing heat loss caused by the degradation of insulation performance due to sweat in extremely cold working conditions. As a result, the closed-pore microstructure provides a low thermal conductivity of 0.039 W/(m·K). Meanwhile, the gradient pores create Laplace pressure difference during water diffusion, driving unidirectional moisture transport and achieving excellent one-way transport index (1082%) and moisture permeability (>4000 g/(m²·24h)). Foam-TEX also demonstrates excellent stability under alternating extreme temperature conditions (-196 to 100 °C), washing, and wringing. This approach provides a flexible and scalable platform to extend the capabilities of Foam-TEX (e.g., Joule heating) to accommodate a variety of extreme wearing scenarios.