Posted: Jun 25, 2014 |
Sound waves harnessed to enable precision micro- and nanomanufacturing (w/video)
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(Nanowerk News) In a breakthrough discovery, researchers at RMIT University in Melbourne, Australia, have harnessed the power of sound waves to enable precision micro- and nano-manufacturing.
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The researchers have demonstrated how high-frequency sound waves can be used to precisely control the spread of thin film fluid along a specially-designed chip, in a paper published today in Proceedings of the Royal Society A ("Double flow reversal in thin liquid films driven by megahertz-order surface vibration").
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Researcher Dr Amgad Rezk with the lithium niobate chip.
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With thin film technology the bedrock of microchip and microstructure manufacturing, the pioneering research offers a significant advance -- potential applications range from thin film coatings for paint and wound care to 3D printing, micro-casting and micro-fluidics.
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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.
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"By tuning the sound waves, we can create any pattern we want on the surface of a microchip," Professor Friend said.
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"Manufacturing using thin film technology currently lacks precision - structures are physically spun around to disperse the liquid and coat components with thin film.
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"We've found that thin film liquid either flows towards or away from high-frequency sound waves, depending on its thickness.
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"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."
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This video shows the behaviour of a drop of fluorescent silicon oil when struck with high frequency sound waves at 30MHz (magnification x30).
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The new process, which the researchers have called "acoustowetting," works on a chip made of lithium niobate - a piezoelectric material capable of converting electrical energy into mechanical pressure.
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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.
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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.
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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.
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