Cassie-to-Wenzel transition of liquid metal on laser-structured substrates via water evaporation for reducing thermal contact resistance

Ga-based liquid metal has attracted widespread attention in thermal management owing to its high thermal conductivity. However, its ultrahigh surface tension hinders effective wetting on structured surfaces. Air gaps are easily created at the solid/liquid interface, thereby increasing the thermal contact resistance. In this study, the wettability of liquid metal is controlled by laser irradiation and water evaporation. The real contact area of solid surface is improved by a femtosecond laser, and liquid metal is infiltrated into microstructures through negative pressure generated by water evaporation. The resultant surfaces exhibit a higher adhesion to liquid metal and a higher thermal conductivity compared to the original surfaces. This approach offers a promising pathway for advancing liquid metal-based thermal management systems.