Toward soft, stretchable and resilient high filled composite gels for potential application as thermal interface materials

Due to the different coefficients of thermal expansion between the heat generation and heat dissipation units, the applications of soft high filled composite gels as thermal interface materials require both high stretchability and excellent resilience. However, high stretchable composite gels reported far usually contain sacrificial species to dissipate energy, thus compromising their resilience. Herein, a soft (0.13 MPa), stretchable (172%), and resilient (>70%) composite gel with ultrahigh filler loading (90 wt%) is developed. The stretchability and resilience are realized by lengthening free polymer strands to form appropriate entanglements, in which the loose entanglements transfer the applied force into a large area and the stiff crosslinks prevent the entanglements from disentangling. In additional, the reversible elasticity of the filler network also dictates the resilience, so delaying its deconstruction allows for excellent resilience. The ultrahigh filler loading also endows the composite gel with high thermal conductivity (4.04 W·m−1·k−1), and the potential of the as-prepared composite gel for a TIM is discovered.