When water droplets hit a lotus flower, they bead up and roll off, carrying away dirt without actually wetting the flower.

Perhaps that's why the lotus, with its nature-given ability to "self-clean," is a symbol of purity in Asian culture.

Scientists long have been fascinated with self-cleaning in nature and hope to someday replicate it in such man-made materials as countertops, walls and laboratory equipment.

They're now closer to that goal thanks to the work of a University of Nebraska-Lincoln chemistry professor and scientists from RIKEN, a research foundation in Japan.

UNL researcher Xiao Cheng Zeng and four Japanese colleagues published the results of their work this month in the online edition of the prestigious Proceedings of the National Academy of Sciences.

"We want to learn from nature," Zeng said in his Hamilton Hall office as he presented a slideshow of flowers and insects that can resist water, a characteristic scientists call hydrophobia.

Some insects, for instance, have hydrophobic legs, allowing them to walk effortlessly on water.

In 2005, while Zeng was visiting RIKEN during his year as a Guggenheim Foundation fellow, he and his team dreamed up the idea to try to simulate hydrophobia on a computer.

If they could, he said, engineers would gain important clues on how to create man-made hydrophobic materials.

Zeng's team spent four years testing thousands of computer simulations, watching how different "structures" reacted when hit with virtual "droplets."

They conducted their experiments on RIKEN's supercomputer, one of the world's fastest.

UNL's supercomputer, PrairieFire, debuted as the world's 107th-fastest in 2002, but since has fallen out of the top 500.

The supercomputer at the Peter Kiewit Institute on the University of Nebraska at Omaha campus is ranked No. 154.

Ultimately, Zeng's team was able to document certain structural properties necessary to achieve hydrophobia.

What that means, Zeng said, is this: Water resistance found in nature can be replicated on a tiny scale.

And what that means is engineers may someday be able to build self-cleaning machines for nanoscientists, who study the tiniest particles of matter.

Self-cleaning machines would be beneficial to nanoscientists because cleaning them by hand is a meticulous, time-consuming process, Zeng said.

Eventually, more self-cleaning materials, including fabrics - raincoats are one example already on the market - and such home items as rooftops or windows may be on the way, Zeng said.

Even tiny robots that can walk on water could someday be a reality.

What about clothes that don't need to be laundered? Carpet that cleans itself after the dog tracks in dirt?

Well, there's no harm in dreaming big.

"This is futuristic research," Zeng said with a chuckle.

"Once you find something interesting, it's very rewarding. That's part of doing science - the fun.

"We want to get the secrets of nature."

Reach Melissa Lee at 473-2682 or mlee@journalstar.com.