Water, a vortex device used to create gold nanoparticles

In an article published in the magazine Little Sciencethe group explains that different sizes and forms of gold nanoparticles were developed based on different VFD processing parameters and concentrations of gold chloride solutions.

“Thanks to this research, we discovered a new phenomenon in a vortex fluid device. A photocontact electrification process at the solid-liquid interface that can be used in other chemical and biological reactions,” Badriah Mazen Alotaibi, lead author of the study, said in a media statement. “We also managed to synthesize pure, pristine gold nanoparticles in water in the VFD, without the use of commonly used chemicals, thus minimizing waste.”

According to Alotaibi, this method is important for the creation of nanomaterials in general, because it is an ecological, fast, scalable process and allows obtaining nanoparticles with new properties.

He explained that the size and shape of gold nanoparticles are crucial for a range of applications – from drug delivery to catalysis, sensing and electronics – due to their physical, chemical and optical properties.

Created a decade ago by the paper’s senior author and Flinders University professor Colin Raston, the vortex flow device is a rapidly rotating tube open at one end through which fluids are delivered by jet power sources. Various rotational speeds and external applications of light within the device can be used to synthesize particles to specification.

“Researchers around the world are now discovering that the continuous-flow thin-film flow device is useful in exploring and optimizing more sustainable processing techniques at the nanoscale,” Raston said. “In this latest experiment, we hypothesize that high shear regimes in VFDs have led to a quantum mechanical effect known as contact electrification, which is another exciting development.”

According to the scientist, this discovery represents a paradigm shift in the production of materials in a controlled manner using water and without the use of other chemicals.