By Will Soutter
Researchers at the University of Sydney have developed a new nanostructured material which uses "raspberry particles" to trap water droplets on its surface, with potential applications from preventing condensation to rapid, portable medical tests.
The structure of the new nanomaterial was designed to mimic the surface of rose petals, which cause water to bead up into droplets.
The raspberry particles, so called because of their raspberry-like shape, are very similar to the structures found on the surface of rose petals. When water lands on the petals, it beads up into round droplets, because the surface is so water-repellent.
The research team examined the fascinating material properties of this natural surface, and replicated the structure using micro- and nanoparticles. The result was the raspberry particles, which interact with water in some very interesting ways.
On surfaces coated with a film of the raspberry particles, water forms the same spherical droplets, which are then held onto the surface like sticky tape - even if the surface is held upside down!
The researchers say that this ability to trap water on a surface could have a huge number of applications, from preventing condensation in critical environments like aeroplane cabins, to enabling cheap, fast and portable medical tests by holding droplets of liquid stationary on a surface for analysis.
Importantly, the researchers are confident that their technology is ready to scale to commercial production soon. Dr Andrew Telford, from the University of Sydney's School of Chemistry, said:
"Our team's discovery is the first that allows for the preparation of raspberry particles on an industrial scale and we are now in a position where we can prepare large quantities of these particles without the need to build special plants or equipment".
Dr Telford is the lead author of the paper about the research, published recently in Chemistry of Materials. His team consisted of colleagues from the School of Chemistry, and Dr Chris Such from Dulux Australia, who were supporting the research.
Dr Telford believes that there is also potential to expand on the knowledge gained in this project, to develop more nanostructured surfaces with specifically tailored properties:
"If we use this nanotechnology to control how a surface is structured we can influence how it will interact with water - for example, we could design a surface that stays dry forever, one that never needs cleaning, or one that can repel bacteria or even prevent mould and fungi growth.
"We could then tweak the same structure by changing its composition so it forces water to spread very quickly. This could be used on quick-dry walls and roofs which would also help to cool down houses.
"This can only be achieved with a very clear understanding of the science behind the chemical properties and construction of the surface."