Exploring the surface and core properties of liquid metals

Gallium based liquid metals and their alloys offer extraordinary features originated from their electron and ion-rich metallic core, fluidity and their surfaces that can interact with the surrounding environments. However, their physical and chemical behaviours under different external stimuli are yet to be fully studied. Hence, further research is necessary for exploring the surface and core properties. In this thesis, the author presents three liquid metal-based systems, shows the outcomes of the studies of incorporation of liquid metals in these systems by taking advantage of liquid metals for developing novel functionalities. In the first stage of this PhD thesis, the author aims to establish an ultrasonication based method for producing gas-sensitive metal oxides coated liquid-metal micro and nanodroplets. The author reveals the tuneability of liquid metal droplets’ size and electronic properties in the process. The gas-sensing performance is investigated under different concentrations of H2 gas and various temperatures. It is shown that gallium based liquid metals can be used for improving the gas sensing functionality by enhancing the surface to volume ratio and forming defects in metal oxides. In the next stage, this PhD thesis is extended to control the extrusion of liquid metals into flexible and stretchable wires. A set-up for electrical extrusion of liquid metal wires with tuneable surface oxide thicknesses and morphologies is shown and characterised. The author then successfully uses this set-up to demonstrate liquid wire patterning and encapsulating the liquid metal wires in a thin layer to present their self-healing properties. In the final stage of this research, The author successfully presents a novel continuous flow reactor based on a liquid metal droplet that promotes both mass transport and reaction. The author of this thesis investigates the concept of liquid metal deformation control, Marangoni flow and its reactive surface in aqueous electrolyte for activating precursors into valuable products. Collectively, the author successfully demonstrates several important scientific findings based on gallium based liquid metals and also builds several novel systems in this PhD thesis, which can potentially impact the future of many fields including material synthesis, additive manufacturing, and also chemical processing