Better materials for industry
Professor Debra Bernhardt from the University of Queensland has been using Raijin and its predecessors for more than 20 years. Her latest work is helping design better materials for industry.
“We use Raijin as an experimental tool to propose and test new materials for applications such as battery technologies, detection of toxic molecules, and conversion of CO2 into useful chemicals,” she says.
Post-doctoral researcher Dr Tanveer Hussain is leading the group’s investigation into the design of ‘nanosensors’ based on nanosheets, which can be used to detect potentially harmful substances in our environment.
“There are many compounds that may not be toxic in everyday life or in low amounts, but they might be undesirable in a particular environment,” explains Professor Bernhardt.
“For example, caffeine is fine in your everyday coffee, but you probably wouldn’t want to find too much of it in an anaesthetic.”
Many biologically relevant molecules, including caffeine, nicotine and ethanol, bind weakly to two-dimensional nanosheets such as graphene.
Upon binding, the electronic properties of the nanosheets change – providing a clear signal that the molecule of interest has been detected.
Nanosheets are ideal for use as sensors because of their extensive surface areas, explains Professor Bernhardt.
“Because these materials are almost entirely made up of surfaces, you can have a very large sensory area that’s still compact and light weight,” she says.
Key to creating better nanosensors is identifying ways to increase the specificity and strength of the bond between the chemical and the nanosheet, which is where computer modelling comes to the fore.
“At the moment, the exact nature of the binding of some substances and their effect on the electronic properties of the nanosheet is still unknown,” says Professor Bernhardt.
“There’s a strong need to study and understand this interaction to design efficient nanosensors.”
The group’s current projects could never have been performed using the supercomputers of the past, says Professor Bernhardt.
“Back in the 90s I was working on small alkali metal cations,” she says. “They’re only found in extreme situations such as fusion reactors or lasers, but we looked at them partly because they were small enough that we could actually perform the necessary calculations.
“Now my students and postdocs are working on more commonplace systems, with large biomolecules or structures; it would have been impossible to study nicotine on graphene back in those early days.”