So Long Washing Machine, Hello Sunshine

MICHAEL D. WHEELER, MANAGING EDITOR, michael.wheeler@photonics.com

Imagine hanging your clothes on the line for laundering instead of drying.

As futuristic as it sounds, that may one day be a reality thanks to recent findings from a research team at RMIT University in Melbourne, Australia. The work could lead to nano-enhanced textiles that can clean themselves when put under light or worn in the sun.

The red color indicates the presence of silver nanoparticles. Image magnified 200×.

Led by Rajesh Ramanathan, Ph.D., the team developed a cheap and efficient way to grow special nanostructures based on copper and silver, which absorb visible light.

“When the nanostructures are exposed to light, they receive an energy boost that creates ‘hot electrons,’” Ramanathan told Photonics Spectra. “These energetic ‘hot electrons’ release a burst of energy that enables the nanostructures to degrade organic matter.”

Cotton textile covered with nanostructures invisible to the naked eye. Image magnified 200×.

This burst of energy effectively eliminated organic compounds in a matter of minutes.

“Some of the basic dyes we tested were degraded within six to 10 minutes under a common LED light,” Ramanathan said. “We are currently in contact with several industries and are doing testing more rigorously on other common stains such as wine, ink and sauce.”

Heretofore, the challenge for researchers had been figuring out how to build the structures outside of a lab and in such a way to easily scale up for commercial applications. To do this, the researchers employed a novel technique that involved dipping the textiles into several different solutions. The result was the development of stable nanostructures within 30 minutes.

Close-up of the nanostructures grown on cotton textiles by RMIT University researchers. Image magnified 150,000×.

Ramanathan noted that the process itself is fairly simple and he envisions it would be easy for industries to incorporate the approach into current manufacturing processes. The first commercial products incorporating the nanostructures may come within three to five years.

Until then, hold on to your Whirlpool.