Shape-memory phase change material enhanced by MWCNT for solar photothermal conversion

The efficient use of solar energy can alleviate the energy shortage, so the photothermal conversion materials have been a hot spot for research. Improved thermal conductivity and higher enthalpy/flexibility can expand the practical application scenarios of photothermal conversion materials. Therefore, a flexible composite material for photothermal conversion is developed in this paper. Among them, carbon nanotube (MWCNT) is the photothermal conversion material, melamine foam (MF) is the supporting skeleton of the composite, and paraffin wax (PW) is the phase change material. According to the results, MWCNT/MF/PW has a high latent enthalpy of 240 J/g. The thermal conductivity of MWCNT/MF/PW (0.129 W/m·K) was improved by 95.5% compared to MF/PW (0.066 W/m·K). MWCNT/MF/PW have a high photo-thermal conversion efficiency (85.16%). Hence, MWCNT/MF/PW exhibit excellent shape recovery due to the response to light and heat. In addition, the outdoor light absorption experiment of the composite PCM water tank indicates that MWCNT/MF/PW as a shell wrapped water tank shows good light absorption and heat preservation effect, which is not available for general photothermal conversion materials.