Epoxy Resin-Based Gel Phase Change Material for Strong Interface Bonding and Interface Thermal Management

Phase change materials (PCMs) play a crucial role as thermal interface materials (TIMs) because of their excellent thermal storage capacity. The solid–liquid phase change materials (SLPCMs) are usually encapsulated in the form-stable supporting materials to avoid leakage. However, plasticity is needed to ensure tight adhesion with the thermal dissipation surface of TIMs, which challenges the SLPCMs encapsulation requirement. Herein, we designed an epoxy resin-based gel PCM by using magnolol bifunctional epoxy resin (DGEM) with crystallizable side chains and 1-(3-aminopropyl) imidazole (IM) as both the extender and curing agent. IM facilitates smart balancing of the chain extension and cross-linking structure to endow the TIMs with both form-stability and surface adhesion via controllable slight cross-linking. Its preparation process is facile, and the as-prepared epoxy resin gel is stable in service. A latent heat storage capacity of 73.8 J g–1 and bonding strengths of 2.9, 2.9, 1.6, and 1.4 MPa for wood, aluminum, glass, and steel are achieved, respectively. When the temperature rises above the melting point (Tm) of PCM, it shows excellent segment migration and surface adhesion in the gel state, which makes it easily adhere to the heat dissipation surface and fully fill the rough surface gap. Its reversible crystallization can store excessive heat energy and release latent heat so that the device temperature is maintained within a relatively safe range. In addition, it can be easily recovered from the bonding substrates once heated above the Tm. Its installation and recovery processes are as efficient as hot melt and pressure sensitive adhesives. This study is of great significance for the preparation and application of PCMs.