Recyclable, Flexible and Highly Thermally Conductive Phase Change Composites with Dynamic Networks for Thermal Management

Flexible phase change materials (PCMs) have become increasingly critical to address the demand for thermal management in electronic technologies and energy conversion. However, their application remains challenging because of their rigidity, liquid leakage, and insufficient thermal conductivity. Herein, flexible glutamic acid@natural rubber/paraffin wax (PW)/carbon nanotubes-graphene nanoplatelets (GNR/PW/CGNP) phase change composites with high thermal conductivity, excellent shape stability, and recyclability were reported. Zn²⁺-based dynamic crosslinking was constructed through the reaction of zinc acetate and carboxyl groups on glutamic acid@natural rubber (GNR), which was used as a flexible matrix to physically blend with paraffin wax/carbon nanotubes/graphene nanoplatelets (PW/CGNP) to achieve uniform dispersion of PW/CGNP, continuous thermal conductivity networks, and good encapsulation of PW. The GNR/PW/CGNP composites showed excellent mechanical strength, flexibility, and recycling ability, and effective encapsulation prevented the outflow of melted PW during the phase transition. Also, the phase change enthalpy could attain 111.1 J/g with a higher thermal conductivity of 1.055 W/mK, 428% higher than that of pure PW owing to the formation of efficient thermal conductive pathways, which exhibited outstanding thermal management performance and superior temperature control behavior in electronic devices. The developed flexible composite PCMs may open new possibilities for next-generation flexible thermal management electronics.