Washington, November 27 : Carnivorous plant Venus flytrap, which closes its leaves to catch insects within a split second, has inspired scientists to make a microscopic lens that can pop instantly between convex and concave.
Carnivorous plant Venus flytrap, which closes its leaves to catch insects within a split second, has inspired scientists to make a microscopic lens that can pop instantly between convex and concave.
Alfred Crosby, assistant professor of polymer science and engineering at the University of Massachusetts in Amherst, said that a polymer coating made from thousands or millions of such lenses could be made into a range of applications, including paints that change colour or even pop off a surface on command, or road signs that change with the light or temperature.
"This snap mechanism allows you to have a very small change in pressure lead to a very large effect. This hasn't been previously done in terms of surface properties," Discovery News quoted him as saying.
For making such lens, the researchers use the same rubbery material as is used to caulk bathroom tiles and tubs. A flat sheet is taken, and an organized patter of little depressions is created in the surface.
After that, the material is inflated like a balloon. During this stage, a polymer is bonded to the patterned material. Little domes of polymer from above each depression are created when the stretching is stopped and reversed.
Finally, the polymer is treated with a chemical that removes a very thin layer from the surface. That changes the pressure and at a critical point, the mounds all snap into a concave shape.
"This is completely novel. There are definitely surfaces that people apply voltages to that release drugs from individual wells, but not surfaces that have the snapping effect. I've never seen anything like that before," said Jeffrey Karp, director of the Laboratory for Advanced Biomaterials and Stem Cell-Based Therapeutics at Harvard University in Cambridge, Massachusetts.
"I don't think there are limitations in terms of what can be done. The next stage is really picking an application and moving into product development. It's a great milestone," Karp added.
As of now, each depression is about the diameter of a human hair. Crosby wants to reduce the size, so that each dome would be hundreds of times smaller.
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