Covalently Functionalized Leakage-Free Healable Phase Change Interface Materials with Extraordinary High Thermal Conductivity and Low Thermal Resistance.

Phase change material (PCM) has received considerable attention to take advantage of both pad-type and grease-type thermal interface materials (TIMs). However, the fatal drawbacks of leaking, non-recyclability, and low thermal conductivity (κ) hinder industrial applications of PCM TIMs. Here we report leakage-free healable PCM TIMs with extraordinary high κ and low total thermal resistance (R t ). The matrix material (OP) is synthesized by covalently functionalizing octadecanol PCM with polyethylene-co-methyl acrylate-co-glycidyl methacrylate polymer through the nucleophilic epoxy ring opening reaction. The OP changes from semi-crystalline to amorphous above the phase transition temperature, preventing leaking. The hydrogen-bond forming functional groups in OP enable nearly perfect healing efficiencies in tensile strength (99.7%), κ (97.0%), and R t (97.4%). The elaborately designed thermally conductive fillers, silver flakes and multiwalled carbon nanotubes decorated with silver nanoparticles (nAgMWNTs), are additionally introduced in the OP matrix (OP-Ag-nAgMWNT). The nAgMWNTs bridge silver flake islands, resulting in extraordinary high κ (43.4 Wm -1 K -1 ) and low R t (30.5 mm 2 KW -1 ) compared with PCM TIMs in literature. Excellent heat dissipation and recycling demonstration of the OP-Ag-nAgMWNT is also carried out using a computer graphic processing unit. The OP-Ag-nAgMWNT is a promising future TIM for thermal management of mechanical and electrical devices. This article is protected by copyright. All rights reserved.