Epoxy Resin-Based\nGel Phase Change Material for Strong\nInterface Bonding and Interface Thermal Management

Phase change materials (PCMs) play a crucial role as\n thermal interface\nmaterials (TIMs) because of their excellent thermal storage capacity.\nThe solid–liquid phase change materials (SLPCMs) are usually\nencapsulated in the form-stable supporting materials to avoid leakage.\nHowever, plasticity is needed to ensure tight adhesion with the thermal\ndissipation surface of TIMs, which challenges the SLPCMs encapsulation\nrequirement. Herein, we designed an epoxy resin-based gel PCM by using\nmagnolol bifunctional epoxy resin (DGEM) with crystallizable side\nchains and 1-(3-aminopropyl) imidazole (IM) as both the extender and\ncuring agent. IM facilitates smart balancing of the chain extension\nand cross-linking structure to endow the TIMs with both form-stability\nand surface adhesion via controllable slight cross-linking. Its preparation\nprocess is facile, and the as-prepared epoxy resin gel is stable in\nservice. A latent heat storage capacity of 73.8 J g<sup>–1</sup> and bonding strengths of 2.9, 2.9, 1.6, and 1.4 MPa for wood, aluminum,\nglass, and steel are achieved, respectively. When the temperature\nrises above the melting point (<i>T</i><sub>m</sub>) of\nPCM, it shows excellent segment migration and surface adhesion in\nthe gel state, which makes it easily adhere to the heat dissipation\nsurface and fully fill the rough surface gap. Its reversible crystallization\ncan store excessive heat energy and release latent heat so that the\ndevice temperature is maintained within a relatively safe range. In\naddition, it can be easily recovered from the bonding substrates once\nheated above the <i>T</i><sub>m</sub>. Its installation\nand recovery processes are as efficient as hot melt and pressure sensitive\nadhesives. This study is of great significance for the preparation\nand application of PCMs.