Minimizing Interface Thermal Resistance Via Laser Surface Micropatterning for Enhancing Wetting of Gallium-Based Liquid Metal with Copper

Thermal management systems are facing significant demand to dissipate increasing heat fluxes in time, however, heat transfer between solid surfaces is always obstructed due to the unperfect interfacial con-tact. Gallium-based room-temperature liquid metals (LM) are a type of emerging thermal interface ma-terials (TIMs) with superior thermal conductivity and deformability, efficiently enhancing the through -interface thermal transfer. However, the poor wettability of LMs with engineering materials (e.g., copper), which leads to non-negligible remaining gap/air at the interfaces, limits the further reduction of thermal interface resistance. Herein, a laser micropatterning approach is presented to significantly improve LM wetting behaviors with copper surfaces in the assistance of HCl solution, with the thermal interface re-sistance minimized to & SIM;0.37 mm2 & BULL;K/W which is four orders of magnitudes lower than that of two bare surfaces directly contacted and a quarter of that of bare surfaces with LM as TIM. Micropatterns featuring dense, shallow and open channels were designed and demonstrated to effectively expel trapped air while using a small amount of LM, which were both found necessary for reducing thermal interface resistance. We believe this study can lay a foundation for the further development and practical application of LMs based thermal management strategies.& COPY; 2023 Elsevier Ltd. All rights reserved.