Two Barriers Against the Cracking of Phase Change Materials Based on Gel Skeleton

Abstract

A novel room-temperature flexible, self-healing PCM (denoted as PEG/PHMAC) based on gel skeleton was prepared in one-pot free-radical polymerization by using acrylic acid (AC) and hydroxyethyl methacrylate (HM) as monomers and polyethylene glycol (PEG) as phase change component and solvent. The as-prepared samples exhibit excellent flexibility with a bending angle of up to 120° without fracture at room temperature, playing the role of the first barrier to effectively alleviate material fracture and failure caused by stress accumulation; in addition, because of the abundant hydrogen bonds in the material, it demonstrates outstanding self-healing ability that deep rift can be quickly repaired within 30 min after the phase change, acting as the second barrier to self-heal the cracks of PCM generated during long-term heat storage/release cycles. Apart from that, these materials also show extraordinary antileakage and shape-stable property without observation of any leakage or deformation at temperature much higher than the phase change temperature. It is also proved that this gel is suitable to act as adsorption skeleton of other PEG with different molecular weight and melting point feasible for different application scenarios. With so many merits, it is expected to provide some innovative ideas for the progress of PEG-based PCM.