Voltage-Assisted Sonication for the Generation of Liquid Metal Particles

Mechanical agitation effectively breaks up bulk liquid metal into small particles that can be used for various applications. Although voltage is known to reduce surface tension in gallium (Ga)-based liquid metals and affects sonication-induced fragmentation, this effect remains unexplored. This study employs ultra-high-speed imaging (as high as 100,000 frames per second) to investigate particle formation under different liquid metal surface tension values influenced by the applied negative, zero, and positive voltages. Negative voltage enhanced particle generation, nearly doubling the solution turbidity compared to the zero-voltage case. Negative voltage and secondary metal inclusion [indium, zinc (Zn), and tin] in liquid Ga reduced the surface tension, increased particle generation, and decreased the particle size. Surface characterization confirms compositional differences, revealing distinct migration and oxidation behaviors of the secondary metals. Notably, Ga-Zn particles undergo significant migration of Zn to the surface, forming Ga-Zn oxide structures. A proof-of-concept demonstration highlights the difference in annealed synthesized particles for photocatalysis, illustrating one potential application of the process. The findings provide insights into voltage-assisted sonication synthesis, enabling the controlled design of liquid metal particles for various applications.