Superhydrophobic Copper Foam Supported Phase Change Composites with High Thermal Conductivity for Energy Storage

Superhydrophobic and superoleophilic oxidized copper foam (OCF) was prepared by oxidation of copper foam using (NH4)2S2O8 to generate rough surface then followed by modification with low surface energy substance polydimethylsiloxane (PDMS) and stearic acid (SA). Based on sperwetting, form-stable phase change materials (PCMs) composites were obtained by facile absorbing of organic PCMs into PDMS-OCF network. In this way, the organic PCMs can be spontaneously adsorbed and remain stable without leakage even at high temperature over their melting points, and the thermal storage capacity of the as-synthesized PCMs composites were analyzed using a differential scanning calorimeter (DSC). The latent heats of the PDMS-OCF/PCMs composites were measured to be 36.87 J g-1 and 36.81 J g-1 for PDMS-OCF/paraffin and PDMS-OCF/SA, respectively, which is greater than that of untreated copper form (CF)/paraffin composite (8.50 J g-1). The PDMS-OCF/PCMs composite shows better thermal stability and the loaded organic PCM has been reduced by 0.64% after 100 times of melting-cooling recycling for PDMS-OCF/paraffin. The thermal conductivity of PDMS-OCF/paraffin composite is about 9 times that of pure paraffin. Such excellent thermal conductivity as well as good thermal stability of the PDMS-OCF/PCMs makes it promising candidate for thermal energy storage.