Synergistic Surface-Interface Engineering within Self-Assembled Carbon Nanofiber Film for Efficient and Robust Phase-Change Cooling

Films with nanoengineered surfaces hold promise for enhancing phase-change cooling and offering a solution to the bottleneck of efficient thermal management in high-power electronics and energy systems. Interfacial thermal resistance between substrates and films, however, hinders further enhancement of heat dissipation during the phase-change process. Furthermore, rapid phase-change bubble detachment at high heat fluxes generally causes peeling off of films and performance deterioration. Here, we developed a uniform carbon nanofiber film (CNFF) on a copper substrate via a facile and low-cost bubble-induced self-assembly strategy and medium-temperature annealing process for efficient phase-change cooling by synergistic surface-interface engineering. The CNFF with micro/nanoporous morphology showed superwetting to electronic fluorinated liquid and ultralow under-liquid bubble adhesion force. Additionally, C-O-Cu covalent bonding can be generated at the copper/CNFF interface due to the interfacial interaction between copper and carboxyl-functionalized carbon nanofiber during annealing of CNFF. This reliable bonding not only decreased interfacial thermal resistance between copper substrate and CNFF but also enabled robustness of CNFF against bubble detachment and liquid jetting. Therefore, the CNFF achieved the simultaneous enhancement of the critical heat flux and heat transfer coefficient up to 47.1 W/cm² and 46.6 kW/(m²·K) with enhanced ratios of 121.1 and 380.4% over the pristine copper, respectively. Based on surface-interface engineering on CNFF, high-performance and long-term phase-change thermal management for high-power chips was finally accomplished. It is expected that the advancement in phase-change heat transfer by combining nanoengineered surfaces with interfacial covalent bonding in this work can provide an energy-efficient path for next-generation electronics cooling.