Enhanced interface heat transfer based on gallium-based liquid metal infiltrated into vertically aligned copper nanowire arrays

Owing to the high aspect ratio and thermal conductivity, copper nanowires have great potential as novel thermal conductivity fillers. However, the thermal conductivity of thermal interface materials (TIMs) prepared by copper nanowires with polymer matrices is low. In contrast, gallium-based liquid metal has a higher thermal conductivity than polymer, while it is difficult to wet copper nanowires with liquid metal to prepare the TIMs. In this study, TIMs with a thickness of 53 µm were prepared by forming a galvanic cell between gallium-based liquid metal and vertically aligned copper nanowire arrays to improve wettability, and the heat transfer performance of the TIMs was experimentally investigated. The results show that the total thermal contact resistance of the composite thermal interface material is as low as 3.20 ± 0.24 mm2K/W. Compared with commercial thermal grease, the total thermal contact resistance is reduced by 86.30 %. The total thermal contact resistance increases with the surface roughness as the actual contact area decreases. In HCl/CuSO4 solution, the wettability of gallium-based liquid metal on the surface of vertically aligned copper nanowire arrays was improved, and the contact angle was 10.1 ± 0.9°. Furthermore, after 360 h of ageing, the total thermal contact resistance of the sample increased by 0.57 mm2K/W. This study provides new directions for designing high-performance TIMs with excellent overall heat transfer properties for the thermal management of electronic equipment.