Controllable dispersion and reunion of liquid metal droplets

Liquid metal (LM) micro-droplets have been widely used in microfluidics, drug-loaded nano-system and micro-nano machine due to its excellent properties. However, there still exist difficulties in succinctly dispersing a bulk of LM into micro-droplets due to the large interfacial tension. Besides, the controllable switching between droplet dispersion and reunion is yet to be realized. Herein, a practical and efficient method for dispersing LM was proposed and the controllable switching between dispersion and reunion of LM droplets was achieved. LM micro-droplets were produced by vibrating the LM immersed in a mixture of N,N-dimethylformamide (DMF) and polyvinyl chloride (PVC). The experimental results show that the size distribution of LM micro-droplets could be tuned by controlling the vibration frequency. More intriguingly, the dispersion and reunion of LM droplets can be switched intelligently through tuning the vibration frequency and amplitude. Furthermore, optical properties of the LM micro-droplet coating were evaluated to display potential applications. A self-driven motion of PVC-coated LM could be achieved by utilizing the produced LM micro-droplets based on the Marangoni effect, which holds promising value for developing future transport tool of LM droplets. The present work suggests an entirely feasible method for dispersing and utilizing LM droplets, which is of great significance for promoting the development of LM micro-droplet science and technology.