Recyclable and Leakage-Resistant Phase Change Materials with Reversible Solid-Gel Transition

Abstract

Phase change materials (PCMs) are critical for thermal management but are prone to leakage in the molten state. Cross-linked polymer networks can effectively encapsulate PCMs, but increasing cross-linking density progressively compromises their latent heat. Herein, we present a facile strategy for encapsulating methoxy polyethylene glycol (mPEG) in a reversible solid-gel transition network with tunable cross-linking density. Taking advantage of the high reactivity between anhydride and amino groups, the cross-linking density of the network can be regulated, allowing the minimum network constraint required for leakage resistance while maximizing the mPEG content and latent heat storage capacity. The resulting PCM achieves a high latent heat value of 143.7 J/g with mPEG loading of 97 wt %. Meanwhile, the dynamic and reversible intermolecular interactions within the network endow the material with excellent leakage resistance and recyclability. After at least 50 grinding-reshaping cycles, both leakage resistance and enthalpy remain essentially unchanged. In the thermal management test, a temperature difference of 8.5 °C is achieved between inside and outside of the model during the heating process. During the cooling process, a constant-temperature plateau lasting 50 min is observed. Benefiting from these advantages, the material exhibits promising prospects for thermal management applications.