Cellulose acetate encapsulated poly(ethylene glycol) phase-change composite materials with tunable transition windows for wearable thermal energy storage

Efficient thermal energy storage materials are crucial for enhancing energy utilization amidst global energy demands. However, practical applications of phase change materials (PCMs) are often hampered by narrow transition windows and leakage risks. In this work, we present a synergistic strategy to concurrently address these challenges by integrating molecular-level phase-change tuning with structural-level engineering design. We encapsulated a blend of poly(ethylene glycol) (PEG) of different molecular weights (PEG2000 and PEG600) within a cellulose acetate (CA) nanofibrous matrix. By strategically adjusting the mixing ratio, we expanded the thermal energy storage window while aligning it with the human physiological thermal comfort range. Concurrently, we constructed a helical yarn architecture via a post-spinning twisting process, providing additional physical confinement that significantly mitigates leakage and enhances the structural integrity of the energy storage system. The fabricated CA/PEG composite phase-change membrane, featuring a 6:4 PEG2000/600 ratio and 60 wt% total loading, exhibited a high melting enthalpy of 62.0 J g −1 . Its melting and crystallization ranges are notably broadened to 34.2–50.1 °C and 18.7–31.8 °C. The resulting energy-storage fabric achieved exceptional leakage resistance, retaining 99.5% of its mass after exposure to 80 °C for 30 min and 96.9% after being wrapped in folded weighing paper and heated in an 80 °C oven for 11 h, while simultaneously ensuring rapid moisture transport with a penetration time of only 0.5 s. In personal thermal management evaluations, the fabric demonstrated a substantially reduced heating rate under solar irradiation, maintaining a 6.2 °C temperature advantage over commercial PET fabric. It also provided substantial thermal buffering effects during cooling phases. These findings underscore that integrating multi-molecular-weight PEG regulation with textile structural reinforcement provides an effective approach for constructing high-performance wearable thermal energy storage materials. • Phase change ranges are effectively tuned by blending varying PEG molecular segments. • Twisted yarn structures provide physical confinement to suppress PEG leakage. • The CA/PEG fabric retains 99.5% mass after 30 min at 80 °C and 96.9% after 11 h. • A maximum cooling effect of 6.2 °C is achieved under intense solar irradiation. • High moisture permeability ensures superior wearing comfort for personal management.