A hierarchical core-sheath structure composite fiber of PW/TPU towards elastic smart thermal management fabrics

Elasticity and stability play a crucial role in phase change fibers (PCFs), ensuring both comfort and effective thermal management in fabrics. In this study, we present the development of an elastic and shape-stable phase change fiber through coaxial wet spinning. The fiber consists of a paraffin wax (PW) core encapsulated in a thermoplastic polyurethane (TPU) sheath, providing reliable protection against leakage during use. The obtained PCFs exhibit a PW loading capacity of up to 64.9 wt% and a heating enthalpy of 117.0 J/g. Notably, these fibers maintain their morphological and thermal stability even after undergoing 50 cycles of heating and cooling treatments. By integrating the PCFs into a fabric and coating the surface with CNTs, the PCFs-based fabric achieves an outstanding photothermal conversion efficiency of 95.1 % under a light intensity of 250 mW/cm2 and an electrothermal conversion efficiency of 73.2 % at a power level of 0.9 W. Furthermore, the fabric, woven with uniformly broken PW core, exhibits excellent tensile resilience in various conditions, including room temperature and during photothermal and electrothermal conversion processes. This study introduces a promising avenue for the development of innovative PCFs, offering significant potential for their application in the realm of personal smart fabrics, particularly in the field of advanced thermal management.