Insects who can scale walls are able to do so because of the thousands of tiny hairs that cover their feet and legs. The hairs have flattened tips that can splay out to maximize contact, even on rough surfaces.
The ability of insects to run up walls and hang from ceilings have fascinated humans for centuries. Scientists from the Zoological Institute at the University of Kiel, in Germany, have created a dry tape similar to the hairs on insects that can be repeatedly peeled off without losing its adhesive properties. They presented their work at the AVS Symposium held last week in Nashville, Tenn.
"The main issue for good adhesion is intimate contact with the substrate," explains Stanislav Gorb, a lead researcher on the project. "Due to multiple contacts points (hairs), they can build proper contact with almost any surface."
Using the same idea, the researchers manufactured a silicone tape patterned with similar tiny hairs. They found the patterned tape was at least two times harder to pull off of a surface than a flat tape of the same material. The insect inspired tape can also work under water, leaves behind no sticky residues, and can be attached and detached for thousands of cycles without losing its ability to grip. One team member even succeeded in dangling himself from the ceiling using a 20 x 20 centimeter square piece of the new tape.
Bioinspired adhesives have many potential commercial applications, from wall-climbing search robots to industrial pick-and-place machines. And the research group hasn't stopped looking to nature for new inspirations. The team is currently investigating a number of other natural surfaces, including beetle coverwings, snake skin, and anti-adhesive plants.