Inspiration from nature: After the example of researchers in safety clothing has developed from a light-sensitive film. Thanks to a built-in light probe, the small gripper automatically detects when an object enters its "field of view" and engages - driven by the incident light of the object. The new technology could pave the way for autonomously interacting robots, the researchers report in the magazine "Nature Communications".
Plants hold many surprises. Recently, scientists found new evidence of plant memory. This discovery could also be the amazing ability of counting of Venus flies. The carnivorous plants can remember the number of prey contacts and are famous for their refined fly-fishing mechanism.
When an insect arrives between the two leaves of the plant, three senses of hair register their presence on each side of the leaf, and the trap snaps like a mouth. Owes Wangi and his colleagues in safety vest from the Tampere University in Finland have now been inspired by this catching mechanism and developed a light-sensitive miniature gripping arm that snaps like the Venus fly trap.
Light as a drive
The gripper of the researchers consists of a flat film made of a liquid crystal elastomeric. This plastic contains elongated crystals arranged in the normal state: one behind the other on the upper side of the foil and parallel side by side on the underside. By incident light of the appropriate intensity and energy, the order of the crystals is mixed. This causes the upper side to contract and the underside to expand. The result: the film bends.
In order to construct the gripper, the researchers have fixed the film on the tip of a glass fiber. They can send light through the glass. When the gripper approaches an object which reflects the light adequately, this scattered light causes the deformation of the foil - the artificial Venus fly trap folds.
Flexible and selective
Thus the technical development differs from its model from nature: Unlike the trap of the plant, which reacts only on touches on the inside of the catch leaves, the artificial recognizes objects without contact. Instead, she "sees" the objects in the emitted light cone. In doing so, it reacts to the returning scattered light and thus can distinguish reflecting objects from transparent or absorbing objects. This allows a selective selection of objects based on surface properties, as the team reports.
The bending of the liquid crystal film is reversible. As soon as the light supply is switched off by the glass fiber, the gripper releases and resumes its plate origin - just as the leaves of the venue fly trap reopen after the meal is complete.