Flexible and Biocompatible Silk Fiber-Based Composite Phase Change Material for Personal Thermal Management

Phase change materials (PCMs) are regarded as an effective passive personal thermal management strategy. However, the preparation of flexible and biocompatible PCMs remains a great challenge. In this study, a silk fiber (SF)-based composite PCM for wearable personal thermal management was prepared using renewable natural silkworm cocoons and biocompatible capric acid (CA). The SF/CA composite PCM is flexible, biocompatible, and dyeable. The results show that the SF and CA are physically bonded, and the crystal structure of CA is not influenced by SF. The melting phase change enthalpy and temperature of the SF/CA composite PCM are 123.4 J/g and 30.6 °C, respectively. It has excellent shape stability, thermal stability, and cycling stability. Particularly, the SF/CA composite PCM has excellent performance for wearable personal thermal management under three scenarios including variable temperature mode, isothermal mode, and light irradiation mode. It can also reduce the temperature fluctuation of the human body in a hot or cold environment. Therefore, the SF/CA composite PCM has bright application prospects for wearable personal thermal management in hot and cold environments.