Elastic phase-change fibers with thermal energy storage based on a tunable TPU aerogel network constructed via a universal ambient pressure drying strategy

Abstract

Aerogel fibers (AFs) can serve as potential skeletons for loading phase-change materials (PCMs) to construct phase-change fibers (PCFs). However, most AFs lack elasticity, and pore maintenance still relies on specialized drying equipment. Inevitable pore collapse under ambient pressure drying hinders the fabrication of elastic PCFs with high phase-change enthalpy. Herein, a universal binary solvents replacement-ambient pressure drying (BSR-APD) strategy for preparing various AFs using wet spinning was proposed. The TPU AFs (TAFs) based on the BSR-APD strategy can be adapted through vacuum impregnation with solid–liquid PCMs to construct elastic temperature-regulating phase-change fibers (TPCFs). This strategy involves binary solvents with low surface tension to achieve solvents replacement, enabling rapid ambient pressure drying at room temperature to obtain AFs of various polymer matrices with high porosity (72.91–93.10%). As a typical case, the TAF prepared by combining solvent–nonsolvent diffusion kinetics with this strategy exhibits negligible shrinkage (2.51%) and exceptional porosity (74.81%), making BSR-APD an efficient alternative to freeze-drying for obtaining TAFs. TPCF impregnated with n-octadecane exhibits excellent tensile stress (5.25 MPa), elongation at break (635.35%) and phase-change enthalpy (193.2 J g⁻¹). The remarkable flexibility, elasticity and thermal cycle stability of TPCFs make them easy to weave into an intelligent temperature-regulating phase-change fabric. This strategy achieves efficient and scalable production of various AFs and elastic PCFs loaded with PCMs, demonstrating great potential in personal thermal management because it offers simple manufacturing, flexibility and high phase-change enthalpy.