title: Ionic imbalance induced self-propulsion of liquid metals.
abstract: Components with self-propelling abilities are important building blocks of small autonomous systems and the characteristics of liquid metals are capable of fulfilling self-propulsion criteria. To date, there has been no exploration regarding the effect of electrolyte ionic content surrounding a liquid metal for symmetry breaking that generates motion. Here we show the controlled actuation of liquid metal droplets using only the ionic properties of the aqueous electrolyte. We demonstrate that pH or ionic concentration gradients across a liquid metal droplet induce both deformation and surface Marangoni flow. We show that the Lippmann dominated deformation results in maximum velocity for the self-propulsion of liquid metal droplets and illustrate several key applications, which take advantage of such electrolyte-induced motion. With this finding, it is possible to conceive the propulsion of small entities that are constructed and controlled entirely with fluids, progressing towards more advanced soft systems.
authors.affiliation: School of Engineering, RMIT University, Swanston Street, Melbourne, Victoria 3001, Australia.
authors.forename: Ali
authors.initials: A
authors.lastname: Zavabeti
authors.affiliation: School of Engineering, RMIT University, Swanston Street, Melbourne, Victoria 3001, Australia.
authors.forename: Torben
authors.initials: T
authors.lastname: Daeneke
authors.affiliation: School of Engineering, RMIT University, Swanston Street, Melbourne, Victoria 3001, Australia.|Institute of Chemical and Bioengineering, Department of Chemistry and Applied Biosciences, 8093 ETH Zürich, Switzerland.
authors.forename: Adam F
authors.initials: AF
authors.lastname: Chrimes
authors.affiliation: School of Chemistry, Physics and Mechanical Engineering, Queensland University of Technology (QUT), Brisbane, Queensland 4001, Australia.
authors.forename: Anthony P
authors.initials: AP
authors.lastname: O'Mullane
authors.affiliation: School of Engineering, RMIT University, Swanston Street, Melbourne, Victoria 3001, Australia.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhen Ou
authors.affiliation: School of Engineering, RMIT University, Swanston Street, Melbourne, Victoria 3001, Australia.
authors.forename: Arnan
authors.initials: A
authors.lastname: Mitchell
authors.affiliation: School of Engineering, RMIT University, Swanston Street, Melbourne, Victoria 3001, Australia.
authors.forename: Khashayar
authors.initials: K
authors.lastname: Khoshmanesh
authors.affiliation: School of Engineering, RMIT University, Swanston Street, Melbourne, Victoria 3001, Australia.
authors.forename: Kourosh
authors.initials: K
authors.lastname: Kalantar-Zadeh