Hierarchical Core‐Shell Phase‐Change Fibers for Active‐Passive Thermal Management, Multimodal Sensing, and Infrared Camouflage

ABSTRACT The continuous development of smart textiles calls for multifunctional fibers that can simultaneously achieve thermal energy storage, active heating, and real‐time sensing. Using an emulsion‐based wet‐spinning strategy, thermoplastic polyurethane/octadecane/poly(3, 4‐ethylenedioxythiophene): poly(styrenesulfonate)/silver microparticles composite fibers (TOPAFs) with a hierarchical three‐layer core‐shell architecture were prepared. The double diffusion strategy was utilized to achieve synchronous encapsulation of phase change materials. The fibers show a melting enthalpy of approximately 133.0 J g −1 for TOPAF and an elongation rate exceeding 400%. The fiber conductivity exceeded 268.2 S m −1 . Under simulated sunlight exposure, the surface temperature of TOPAF increased from approximately 27.8°C to 41.8°C. At a voltage of 2.0 V, the fiber temperature reached approximately 47.9°C, demonstrating excellent photothermal and electrothermal conversion. Under outdoor sunlight exposure, the surface temperature of TOPAF was on average ∼10.2°C higher than that of cotton fabric. TOPAF exhibited multimodal sensing performance. The flower‐shaped AgMPs made the average infrared absorption rate of TOPAF in the long‐wave infrared band only 5.4%, which is 10.1 percentage points lower than TPU fiber. TOPAF's energy storage and conversion, multimodal sensing and infrared camouflage features provide a solution for textiles to achieve self‐powered temperature management, dynamic thermal camouflage and signal monitoring.