Pitcher plant inspires liquid repelling coatingSeptember 23rd, 2011 - 5:35 pm ICT by IANS
Washington, Sep 23 (IANS) After rainfall, the cupped leaf of the sweet smelling pitcher plant becomes a frictionless surface, enticing ants, spiders and even frogs to their doom. Now it has inspired a liquid repelling coating that could find a range of uses.
Adopting the plant’s slick strategy, a group of Harvard scientists have created the material that repels just about any type of liquid, including blood and oil, even under harsh conditions like freezing temperatures.
The bio-inspired liquid repellence technology should find applications in biomedical fluid handling, fuel transport and anti-fouling and anti-icing technologies.
It could even lead to self-cleaning windows and improved optical devices, the journal Nature reports.
“Inspired by the pitcher plant, we developed a new coating that outperforms its natural and synthetic counterparts and provides a simple and versatile solution for liquid and solid repellency,” says Joanna Aizenberg, who led the study.
Aizenberg is professor of materials science at the Harvard School of Engineering and Applied Sciences (SEAS).
Conversely, current state-of-the-art liquid repellent surfaces have taken cues from a different member of the plant world, according to a Harvard statement.
The leaves of the lotus resist water due to the tiny microtextures on the surface; droplets balance on the cushion of air on the tips of the surface and bead up.
The so-called lotus effect, however, does not work well for organic or complex liquids. Moreover, if the surface is damaged (e.g. scratched) or subject to extreme conditions, liquid drops tend to stick to or sink into the textures rather than roll away.
Finally, it has proven costly and difficult to manufacture surfaces based on the lotus strategy. The pitcher plant takes a fundamentally different approach.
“The effect is similar to when a car hydroplanes, the tires literally gliding on the water rather than the road,” says study author Tak-Sing Wong, a postdoctoral fellow in the Aizenberg lab.