Fabricating Thermoconductive Phase-Change Fiber via Solvent-Regulated Encapsulation in Carbon Nanotube Network

Personal thermal management (PTM) systems are pivotal for energy-efficient thermal regulation. However, conventional phase change fibers (PCFs) are limited by insufficient latent heat capacity and phase change materials (PCMs) leakage. To address these challenges, we encapsulated polyethylene glycol (PEG) as a phase change material within a continuous carbon nanotubes (CNTs) network by coagulation bath solvent regulation. After optimizing the CNTs network contraction effect by controlling the ethanol (EtOH)/water content ratio, the resultant PEG/CNTFs (50wt%EtOH) (obtained from a 50 wt % EtOH coagulation bath) synchronously demonstrated a series of attractive features, including a high phase change enthalpy (145.2 J/g), robust tensile strength (487.0 MPa), and outstanding thermal conductivity (59.3 W·m –1 ·K –1 ). The interlaced CNTs architecture endows the fibers with acceptable electrical conductivity (0.62 MS/m), enabling dual-mode thermal regulation by combining passive phase change buffering with active Joule heating. Additionally, the material exhibited high cycling stability, retaining 99.4% of its enthalpy after 500 thermal cycles. Their distinct flexibility and mechanical strength allow them to be woven into large textiles (e.g., 30 cm × 150 cm), highlighting their suitability for wearable PTM applications with combined Joule heating and phase-change buffering. This scalable, one-step fabrication strategy synergizes high energy density, structural resilience, and multifunctionality, positioning PEG/CNTFs as a transformative solution for next-generation smart textiles.