Leakage-Proof and Malleable Polyethylene Wax Vitrimer Phase Change Materials for Thermal Interface Management

Abstract

Solid–liquid phase change materials (PCMs) are widely used in heat management. However, the requirement of no leakage of solid–liquid PCMs during phase transition and suitable deformability at evaluated temperature are contradictory when PCMs are used as thermal interface materials (TIMs). Vitrimer, a kind of material that combines with the advantages of both thermoplastics and thermosets, may be a solution. Herein, polyethylene wax vitrimer (PEWV) is prepared through the dioxaborolane exchange reaction for TIMs with leakage-proof and high-energy-storage ability. Microphase separation occurs between highly cross-linked skeleton and slightly cross-linked chains, which solves the leakage problem of polyethylene wax. Simultaneously, PEWV can achieve a high latent heat storage capacity of about 121.0 J g–1, about 74% of that of PEW, owing to the negligible effect of dynamic cross-linking on the crystallization of PEW. Meanwhile, PEWV can be plastically deformed and tightly adhered to the rigid surface under a slight external force at the phase change temperature, filling the gap at macro- and microscales for improving the heat transfer efficiency. The composites of PEWV and thermal conductive filler show more excellent performance as TIMs than commercial thermal conductive pads. PEWV with no leakage, excellent plasticity, and high latent heat storage capacity provides great application potential in heat storage and thermal interface management.