The green alchemists creating new nanotechnology gold

By Tania Bawden

Flinders University, South Australia

In a surprise discovery, Flinders University researchers in South Australia have produced a range of different types of gold nanotechnology particles by adjusting water flow in the novel vortex fluidic device – without the need for toxic chemicals.

The green chemistry lab work at the Flinders Institute for Nanoscale Science and Technology on nano gold formation also led to the discovery of a contact electrification reaction in water in the device – which resulted in the generation of hydrogen and hydrogen peroxide.

In a new article in Small Science, Australian and overseas scientists collaborated on the developing size and form of gold nanoparticles from various vortex fluidic device (VFD) processing parameters and concentrations of gold chloride solution.

“Through this research, we have discovered a new phenomenon in theVFD. The photo-contact electrificiation process at the solid-liquid interface which could be used in other chemical and biological reactions,” says Flinders PhD Ms Badriah Alotaibi, who led the study.

“We also have achieved synthesis of pure, pristine gold nanoparticles in water in the VFD, without the use of chemicals commonly used – and thus minimising waste,” says Alotaibi.

“This method is significant for the formation of nanomaterials in general because it is a green process, quick, scalable and yields nanoparticles with new properties.”

Gold nanoparticles’ size and shape are critical for a range of applications – from drug delivery to catalysis, sensing and electronics – due to their physical, chemical and optical properties.

The vortex fluidic device, devised a decade ago by senior author Flinders University Professor Colin Raston, is a rapidly rotating tube open at one end with liquids delivered through jet feeds. Different rotational speeds and external application of light in the device can be used to synthesise particles to specification.

“Researchers around the world are now finding the continuous flow, thin film fluidic device useful in exploring and optimising more sustainable nano-scale processing techniques,” says Raston.

“In this latest experiment, we hypothesise that the high shear regimes of the VFD led to the quantum mechanical effect known as contact electrification, which is another exciting development.”

Raston says this discovery “is a paradigm shift in how to make materials in a controlled way using water, with no other chemicals required, which contributes to a more sustainable future”.

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This article is from Flinders University News.