Water-Repelling Technique Relies on Lotus 'Technology'

Scientists at the Duke University have recently managed to establish why lotus leaves can stay dry naturally in the wild, but they seem to lose this ability while in the confined settings of research labs. The team, led by materials scientist Chuan-Hua Chen, determined that the plant essentially made use of the natural vibrations in its environment to shake loose water droplets on its leaves, but that this is not the case in artificial settings, which are especially designed to isolate target objects from external influences, Wired reports.

In the new paper, published in Friday's issue of the respected scientific journal Physical Review Letters, the experts hypothesize that human-made materials could be constructed in the near future in such a manner that they could replicate this natural property. Until now, it has never been shown in the lab that lotus leaves make use of wind-induced vibrations to shake off the water on their surfaces. Chen has been fascinated with the plants even as a small boy growing up in his hometown of Honghu, in central China. He suspected that the wind had an influence, but until now lacked the means to prove it.

“People have observed that condensation forms every night on the lotus leaf. When they come back in the morning the water is gone and the leaf is dry. The speaker reproduced in the lab what happens every day in nature, which is full of subtle vibrations, especially for the lotus, which has large leaves atop long and slender stems,” the expert explained in a press release. In the experiments, the team used a woofer of a $20 Radio Shack speaker, placed underneath the plant, and a high-speed camera.

The speaker vibrated the leaf at a frequency of about 100 Hertz, and the camera recorded in minute detail all of the phenomena that occurred in it as the experiment progressed. Another thing that helps lotus stay dry is its surface structure. It is covered by tiny, rough, fiber-covered pillars, which create cushions of air under the water drops. This means that the drop is not allowed to “stick” to the leaf. The vibrations then come into play, and force the droplets to flow off the plant. “This finding has direct applications because vibration is everywhere. Your computer has fans, it keeps vibrating. Your power plants, your automobile or your spacecraft all have vibrations,” the expert concluded.