Thermal properties and shape stabilization of epoxidized methoxy polyethylene glycol composite PCMs tailored by polydopamine-functionalized graphene oxide

A series of composite phase change materials (cPCMs) are fabricated through the one-pot method with the epoxidized methoxy polyethylene glycol (EmPEG) as the thermal energy unit and polydopamine-reduced graphene oxide (PDA-rGO) nanosheets as the interfacial enhancement. Structure and thermal properties such as phase change enthalpy, thermal repeatability, and light-to-thermal conversion capacity of EmPEG/PDA-rGO cPCMs with PDA-rGO content varying from 0.5 to 4 wt% have been detailed discussed. A superior stabilization performance of EmPEG/PDA-rGO cPCMs to pristine EmPEG is demonstrated based on the interfacial action from the incorporated PDA-rGO nanosheets. EmPEG/PDA-rGO-3 presents good structure-stabilized behavior after 100 heating-cooling cycles, and no liquid leakage appears up to 105 °C. In the meantime, EmPEG/PDA-rGO-3 illustrates a stable thermal reliability and thermal charging/discharging rate, and the light-to-thermal conversion efficiency reaches 96% under the 100 mW/cm² irradiation. Thus, the structure-stabilized EmPEG/PDA-rGO cPCMs tuned by the interfacial interaction demonstrates the promising application in the field of the thermal energy storage and solar energy conversion.