Preparation and properties of erythritol/exfoliated graphite nanoplatelets @ polyaniline microencapsulated phase change materials with improved photothermal conversion efficiency

Multifunctional microencapsulated phase change materials (MePCMs) with sugar alcohols as core and functional polymers as shell are of great importance for the applications of sugar alcohols as phase change materials (PCMs). However, the preparation of such kinds of MePCMs was restricted due to the water solubility and the high phase change temperature of sugar alcohols. Herein, we proposed a facial method and prepared a series of novel multifunctional sugar alcohols @ polyaniline (PANI) MePCMs with m-erythritol (ME) as core, PANI as shell, and exfoliated graphite nanoplatelets (GNPs) as thermal conductive and photothermal conversion enhancement fillers. The prepared MePCMs were composed of GNPs@ME particles microencapsulated by PANI shell when the loading of GNPs was no more than 4 wt%. Otherwise, the GNPs@ME particles would be wrapped by excessive GNPs at first and then microencapsulated by the PANI shell. The prepared MePCMs exhibited good anti-leakage performance. The latent heat storage capacity of the prepared MePCMs could attain 254.3 J·g−1. The thermal conductivity of the MePCMs with 8 wt% GNPs could be greatly enhanced to 196 % higher than that of the MePCMs without GNPs. Meanwhile, due to the synergetic nucleating effect of PANI and GNPs, the supercooling of ME in the MePCM was effectively suppressed from about 100 °C to about 56 °C with 2 wt% GNPs. The prepared MePCMs also exhibited excellent photothermal conversion performance. Consequently, the results reported here could pave the way for the preparation of sugar alcohol-based multifunctional MePCMs for solar thermal applications and latent heat storage systems.