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.