Brick-mortar structured MXene/Chitosan/SiO2@n-eicosane flexible composite film for solar-powered wearable body heat management

Organic phase change materials are widely used in solar energy utilization and thermal management due to their better phase change properties. However, their practical applications are limited by leakage, low thermal conductivity coefficients, and rigidity, so their use in thermal management of wearable devices continues to face major challenges. Therefore, in this paper, a one-step vacuum-assisted filtration method using SiO₂@n-eicosane phase change capsule (PCC) as “brick”, MXene nanosheets as “sand”, and chitosan (CS) as “cement” was used to prepare MXene/Chitosan/SiO₂@n-eicosane (MCP) composite films with temperature regulation. The structural design effectively improves the flexibility and stability of the film. The microcapsule encapsulation of the phase change material effectively prevented the possibility of eicosane leakage, and the synthetic composite films have high phase change enthalpy (73.48 J/g). In addition, due to the incorporation of MXene, the composite film has a high photothermal conversion efficiency (93.2 %). At low temperatures, the composite film can significantly increase the surface temperature of fabrics by 18.5 ± 0.5 °C, higher than that of uncoated fabrics. The composite film shows significant temperature control effect and good thermal management capability. In summary, the MCP films, with their simple preparation process and excellent performance, show great potential for application in low-temperature and solar-driven thermal management.