Liquid metal marbles: a new platform for nanomaterials

Researchers at RMIT University have created ‘liquid metal marbles’ - droplets of liquid metal coated in nanoparticles - in what is claimed to be a world-first breakthrough that advances research into soft electronics and industrial sensing technologies.

The team from RMIT’s Platform Technologies Research Institute combines the concepts of liquid marbles with liquid metal droplets, creating a novel platform by using functional nanoparticles as a semi-solid coating on liquid metals.

The research will be published in the 14 January edition of the journal Advanced Functional Materials.

Lead investigator Dr Vijay Sivan said the liquid metal marbles - which have a highly conductive core and a coating of functional nanoparticles with highly controlled electronic properties - were developed as part of investigations into flexible conductive systems for electronic and electromagnetic units.

“The liquid metal marbles our team has developed are like flexible ball bearings with extraordinary physical properties,” Dr Sivan said.

“They can endure high impacts without disintegrating, can tolerate high temperatures, can operate like semiconducting-conducting systems - the base of transistors - and are compatible with micro- and nanofluidic systems.

“The possibilities this new platform offers are amazing and we look forward to exploring the potential of liquid metal marbles in a range of applications.”

A multidisciplinary team of researchers from the schools of Electrical and Computer Engineering, Applied Sciences, Civil, Environmental and Chemical Engineering, and Media and Communication developed the new platform by covering the surface of liquid metal droplets with selected nanocoatings, resulting in ‘marbles’ that were both non-stick and durable.

“This simple approach overcomes the limitations of droplets and liquid metals and means we can use a broad range of powder-coating materials, from insulating to semiconducting and highly conducting,” Dr Sivan said.

“The idea of building liquid electronics based on liquid metal marbles is unique, as they can not only move and form makeshift electronic devices, they can also produce strong plasmonic fields around them.

“For sensing applications, these marbles are the safest alternative to mercury-based heavy metal ion sensors, while their thermal conduction properties are also fascinating, and should be further investigated.”