Researchers at RMIT University have successfully harnessed the power of high-frequency sound waves to enable precision micro- and nano-manufacturing.
The ground-breaking discovery, which was published on 25 June in “Proceedings of the Royal Society A”, have offered a significant advance potential applications range from thin film coatings for paint and wound care to 3D printing, micro-casting and micro-fluidics.
Professor James Friend, Director of the MicroNano Research Facility at RMIT, said the researchers had developed a portable system for precise, fast and unconventional micro- and nano-fabrication, which harnesses the power of high-frequency sound waves to precisely control the spread of thin film fluid along a specially-designed chip.
“By tuning the sound waves, we can create any pattern we want on the surface of a microchip. Manufacturing using thin film technology currently lacks precision — structures are physically spun around to disperse the liquid and coat components with thin film,” Professor Friend said.
“We’ve found that thin film liquid either flows towards or away from high-frequency sound waves, depending on its thickness. We not only discovered this phenomenon but have also unravelled the complex physics behind the process, enabling us to precisely control and direct the application of thin film liquid at a micro and nano-scale.”
According to the media release by RMIT, the new process, which the researchers have called “acoustowetting”, have worked on a chip made of lithium niobate — a piezoelectric material capable of converting electrical energy into mechanical pressure.
The surface of the chip is covered with microelectrodes and the chip is connected to a power source, with the power converted to high-frequency sound waves. Thin film liquid is added to the surface of the chip, and the sound waves are then used to control its flow.
The research shows that when the liquid is ultra-thin — at nano and sub-micro depths — it flows away from the high-frequency sound waves.
The flow reverses at slightly thicker dimensions, moving towards the sound waves. But at a millimetre or more in depth, the flow reverses again, moving away.