Ultralow CNT-reinforced phase-change fibers for scalable wearable thermoregulation

Phase-change materials (PCMs) demonstrate transformative potential for wearable thermal management systems; however, their practical implementation faces challenges due to trade-offs among energy storage density, mechanical robustness, and phase-change stability. Here, we present a nanotechnology-directed strategy that integrates ultralow carbon nanotubes (CNT, 0.1 wt.%) scaffolds with three-dimensional (3D) interpenetrating polymer networks (IPNs), achieving remarkable synergy between crystallinity control and thermal regulation. The resultant phase-change fibers (PCFs) demonstrate dual-functional optimization. Firstly, they exhibit excellent latent heat storage (∆H_m = 139.0 J·g^-1, ∆H_c = 138.0 J·g^-1) with remarkable thermal stability, enabled by CNT-induced heterogeneous nucleation. Secondly, the PCFs show high mechanical robustness (ɛ = 1530%, σ = 6.32 MPa) and photothermal energy harvesting efficiency (η = 90.5%, at 120 mW·cm^-2). These enhancements are attributed to CNT network-enhanced interfacial thermal coupling. Furthermore, the fibrous architectures enable high-fidelity (>98%) cutting/sewing during textile manufacturing, facilitating scalable production of energy-efficient thermal-regulating fabrics. This establishes a universal framework for scalable smart textiles and bridges the gap between laboratory-level phase-change engineering and industrial-scale wearable thermal systems. This strategy advances the development of self-regulating textiles with on-demand thermal responsiveness, paving the way for next-generation smart fabrics for energy-efficient personal thermal management.