Facile fabrication of shape-stabilized polyethylene glycol/cellulose nanocrystal phase change materials based on thiol-ene click chemistry and solvent exchange

Abstract

How to realize large-scale manufacture of phase change materials (PCMs) with high latent heat storage and excellent shape stability is still a great challenge. Recently, encapsulating PCMs with three-dimensional porous structure is of great interest due to its excellent leak-proof ability and large latent heat storage capacity. However, the conventional fabrication techniques of 3D supporting skeletons for loading PCMs commonly involves hydrothermal process, freeze-drying and vacuum impregnation, which is difficult to operate and costly for large-scale manufacture. Herein, a facile and novel strategy for the potential large-scale manufacture of 3D porous structure supported PCMs is presented. This strategy involves two steps: rapid preparation of a novel CNC hydrogel based on UV-induced thiol-ene click chemistry and direct impregnation of PEG PCMs into the CNC hydrogel using solvent-exchange strategy for the first time. The structure and properties of CNC hydrogels and PEG/CNC hybrid PCMs are characterized. High latent heat, improved thermal conductivity, excellent thermal and shape stability are observed in the PEG/CNC hybrid PCMs. An obvious decrease of the crystalline phase change temperature is also observed due to the strong hydrogen bonding between the well reserved CNC nanofiber network and PEG molecule chains. This solvent-exchange strategy shows great potential in the large-scale manufacture of high-performance and shape-stable PCMs.