Constructing intrinsic solid phase change materials with reprocessability and thermal energy storage through multiple hydrogen bonds and acetals

Abstract

Thermal management in flexible phase change materials (PCMs) for electronic devices necessitates a delicate balance between energy storage capacity, mechanical properties and reprocessability within complex application environments. However, the structural design of most flexible phase change materials only focuses on a single functional requirements and fails to meet the demands for phase change thermal energy storage materials and thermal management devices with multiple different performances. Therefore, we propose a simple and cost-effective strategy is proposed to fabricate intrinsic solid-solid phase change materials (SSPCMs) that balance heat storage, mechanical strength and reprocessability. We prepared a polyurethane matrix using high molecular weight PEG, which is more easily crystallized, and a bio-based acetal diol derived from furfural and 1,6-hexanediol. The introduction of bio-based acetal diols improves energy storage capacity and efficiency. In addition, the matrix contains multiple H-bonds, which act as strong physical crosslinks to enhance the mechanical properties of the flexible PCM. The resultant high-performance phase change materials (HFPCMs), with a polyethylene glycol (PEG) content of 80 wt%, show remarkable latent heat capacity of 134.43 J g⁻¹, a tensile strength of 1034 %, high thermal stability (no significant shape change below 160 °C), and good reprocessability. In the cyclic thermal stability test, it has good reversible stability and cyclic sustainability. Overall, this work provides a new method to development of intrinsic SSPCMs with high energy storage capacity, good mechanical properties, and reprocessability, offering significant potential for advanced thermal management in electronic devices.