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

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

Porous Carbon-Based Phase Change Material Host Matrix from Semicoking Wastewater

The capture and storage of solar energy using phase change materials (PCMs) are very important for cost-effective energy management. However, their low thermal conductivity and liquid phase leakage pose persistent challenges for effectively harvesting thermal energy with PCMs. Herein, using semicoking wastewater-derived phenolic resin (SWPR) as the carbon source and potassium hydroxide as activator, hierarchical porous carbon (HPC) materials with abundant porous structures were synthesized to confine the PCM. The HPCs generated microporous and mesoporous layered cavities that provided more space as well as capillary adsorption and physical interaction for PCM storage. Shape-stable phase change composites (PCCs) were then fabricated by vacuum impregnation of the HPCs with paraffin wax to address the problems of low thermal conductivity and liquid melt leakage. The PCCs exhibited high energy storage densities of up to 84.07 J g–1, dimensional stability, excellent thermal cycle stability, and the phase transition enthalpy of around 80.25 J g–1 after 500 heating–cooling cycles. The carbon support increased the thermal conductivity of the optimum PCC by 166% compared to that of pure paraffin wax. This study provides a cost-effective and environmentally friendly method for shape-stable PCMs based on waste-derived porous carbon materials with potential applications in solar–thermal energy storage