The low melting gallium-based liquid metal (LM) is showing tremendous potential in many technologies due to its unique properties. However, the high surface tensions as well as oxidations result in poor wetting capability on most solid surfaces, which limits its practical application. In this work, a simple chemical method is utilized to enable spontaneous wetting of LM on various metal surfaces, such as copper, nickel, and iron. It is found that LM can spread rapidly on the metal substrates treated with CuCl2 solution through reactive-wetting and metallic bond-enabled wetting mechanism. The redox reaction between Ga and copper compound and the formation of intermetallic compound via LM phagocytosis help drive LM to wet metal substrates spontaneously. Many factors affecting the wetting behaviors of LM, including surface roughness, crystal size, and ambient environment, are systematically studied. This finding provides a novel strategy to solve the wetting problem of LM and will enable wider applications.
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