Novel flexible phase change films with outstanding thermochromic and thermal management performance

With the advancement of high-power-density electronic components such as 5G and AI chips, traditional thermal management materials have shown limitations in process-ability, durability, functionality and reliability. Developing flexible composite phase change materials that combine high thermal conductivity, excellent thermal storage capacity, and good thermal management is extremely crucial. Thus, this study constructed a novel flexible phase change film with interconnected thermal conductive framework by innovatively utilizing flexible polyvinyl acetate (PVA) bonding with boric acid (BA) through hydrogen bonds. Thermochromic ink and molten PEG8000 were also infiltrated and synergistically interconnected into the cross-linking porous structure of PVA/BA, forming multiple function units. These units thereby established a continuous three-dimensional flexible network. As the PEG8000 content was 45 wt%, this composite phase change film exhibited a thermal conductivity as high as 0.7417 W·m −1 ·K −1 , and a phase change latent heat of 72.31 J·g −1 . It simultaneously maintained outstanding reliable cycling performance, excellent thermochromic performance and good flexibility. Thermal management demonstrated that the flexible film could significantly reduce the operating temperature of batteries, offering promising applications in thermal management of electronic equipment. This research also provided an effective solution for the preparation of flexible thermally conductive phase change films.