Facile Green\nStrategy of Fabricating Flexible Phase\nChange Fibers with High Thermal Energy Capacity

The development of high-performance\nphase change fibers\n(PCFs)\nrepresents a significant advance toward achieving intelligent wearable\nthermal management for humans. However, existing PCFs are limited\nby a lot of drawbacks, such as low energy storage capacity, poor flexibility,\nand complex preparation processes. Here, we developed an efficient\nand simple methodology for the preparation of PCFs utilizing a green\nwet-spinning technique. The PCFs are composed of discontinuous octadecane\nmicrocapsules (M18) and a polymer matrix (sodium alginate), endowing\nthe PCFs with excellent flexibility. Additionally, the fibers exhibit\na high energy storage capacity of up to 113.2 J/g, demonstrating a\nmarked improvement over the thermal energy storage capacities of currently\navailable commercial thermoregulating fibers. The PCFs also present\nexcellent shape stability above their melting temperature, confirming\ntheir potential for practical applications. Remarkably, colored PCFs\ncould be obtained by incorporating minor quantities of dyes into the\nspinning solution, thereby improving their practical value. The outstanding\nthermal cycling stability of the PCFs was confirmed by their maintained\nenthalpy after they underwent 100 thermal cycling tests. In a subsequent\ninvestigation, graphene composite PCFs were prepared and evaluated\nfor their thermal management efficacy, revealing their superior thermal\nmanagement capabilities. Our findings contribute valuable insights\nfor the research community and manufacturers toward a simplified and\nefficient production of flexible, high-performance PCFs with broad\napplication potential.