SiO2-shelled nano-encapsulated phase change materials for durable thermoregulating Lyocell fibers via dry-jet wet spinning.

Thermoregulating textiles with high durability and energy storage capability are essential for advanced personal thermal management. However, conventional phase change materials (PCMs) incorporated into fibers often suffer from leakage, poor dispersion, and limited washing stability. In this work, SiO2-based nano-encapsulated phase change materials (NEPCMs) with high encapsulation efficiency were synthesized via a sol-gel method and incorporated into Lyocell fibers through a dry-jet wet spinning process. The optimized NEPCMs exhibited uniform particle sizes of 300-450 nm and a high encapsulation efficiency of 65.9%, enabling successful incorporation within the fiber matrix. The resulting thermoregulating Lyocell fibers achieved a balanced performance, delivering a melting enthalpy of 15.3 J/g at 15 wt% loading while maintaining good mechanical properties. The fibers retained over 98% of their latent heat after 100 thermal cycles and more than 87% after 100 washing cycles, demonstrating excellent durability. In addition, the composite fibers exhibited good resistance to UV aging, preserving over 90% of their mechanical performance. Infrared thermography further confirmed an effective thermal buffering effect, with a delayed cooling response of approximately 80 s. This study provides a robust and scalable strategy for integrating high-performance NEPCMs into regenerated cellulose fibers, offering significant potential for durable and sustainable thermoregulating textile applications.