Injectable Spontaneous Generation of Tremendous Self-Fueled Liquid Metal Droplet Motors in a Moment

TL;DR

This paper introduces a simple, injectable method to spontaneously generate large quantities of self-fueled liquid metal droplet motors in liquid environments, driven by galvanic reactions, enabling new micro-robotic and microfluidic applications.

Contribution

It presents a novel, straightforward technique for creating autonomous liquid metal droplet motors via injection, bypassing complex fabrication processes.

Findings

Droplet motors form within seconds after injection.

Motors are powered by galvanic reactions producing electricity and hydrogen gas.

The method enables scalable production of soft micro-motors.

Abstract

Micro motors that could run in liquid environment is very important for a variety of practices such as serving as pipeline robot, soft machine, drug delivery, or microfluidics system etc. However, fabrication of such tiny motors is generally rather time and cost consumptive and has been a tough issue due to involve too many complicated procedures and tools. Here, we show a straightforward injectable way for spontaneously generating autonomously running soft motors in large quantity. A basic fabrication strategy thus enabled is established and illustrated. It was found that, injecting the GaIn alloy pre-fueled with aluminum into electrolyte would automatically split in seconds into tremendous droplet motors swiftly running here and there. The driving force originated from the galvanic cell reaction among alloy, aluminum and surrounding electrolyte which offers interior electricity and hydrogen gas as motion power. This finding opens the possibility to develop injectable tiny-robots, droplet machines or microfluidic elements. It also raised important scientific issues regarding characterizing the complicated fluid mechanics stimulated by the quick running of the soft metal droplet and the gases it generated during the traveling.