Heat transfer properties of graphene/polyethylene glycol composite phase change material modified by bifunctional titanate coupling agent

The amphiphilic structure of the coupling agent, which is capable of combining two materials with disparate properties to enhance their interfacial compatibility, was employed to modify graphene aerogel for the preparation of a composite phase change material (CPCM), thereby expanding the scope of potential applications for the phase change material. The phase change enthalpy of the prepared CPCM is 163.07 J/g, with 90.02 % of the phase change enthalpy retained and 98.7 % of the heat storage capacity retained after 500 thermal cycles, which is indicative of excellent thermal stability and cycling stability. Concurrently, the coupling agent impedes the volume contraction of graphene aerogel through the formation of hydrogen bonds, thereby enhancing the loading capacity of the aerogel with respect to the phase change material. Furthermore, the incorporation of the coupling agent diminishes the interfacial thermal resistance by augmenting the interfacial interaction and phonon coupling. The thermal conductivity is augmented by 213.8 % in comparison to that of pure PEG. The composite phase change materials prepared exhibit optimal thermal management and thermal storage capacity.