Flexible Phase Change Adhesive Allowing Tunable Melting Point for Flexible Electronics Thermal Management with Controlled Adhesion

Currently, flexible phase-change materials that have been widely investigated for flexible electronics typically exhibit melting points below 60 °C and lack intrinsic interfacial adhesion. These limitations render them inadequate for thermal management under bending, twisting, and other mechanical deformations encountered in flexible devices. To overcome these constraints, we developed a strategy in which novel urea-based phase-change materials (PCMs) were incorporated in situ into a polyacrylate matrix via a solvent-free UV-curing process, thereby constructing a flexible phase-change adhesive (FPCA) that combines strong interfacial adhesion with a tunable melting point covering 60-100 °C. The optimized FPCA formulation (E90A10-H6U-40 wt %) achieves an exceptional combination of properties: high flexibility (tensile strength: 0.44 MPa; elongation at break: 1227%), melt point (74.2 °C), reliable phase change enthalpy (53.4 J/g), strong adhesion (180° peel force: 5.5 N/25 mm at phase-transition temperature), folding endurance exceeding 200 000 cycles, and stable performance after accelerated aging (85 °C/85% Relative Humidity for 168 h). The FPCA series also enables controlled thermal debonding with debonding ratios exceeding 99%, supporting temporary bonding and non-destructive device recycling. This work substantially broadens the material landscape for flexible thermal management and offers a promising pathway toward next-generation, wearable-compatible electronic devices.