In various types of manufacturing, parts are robotically picked and placed using graspers or suction cups. The former can damage fragile items, however, while the latter won't work in vacuums or on rough surfaces. That's why scientists from Germany's Leibniz Institute for New Materials (INM) have developed – well, a new material. It utilizes the same principle as sticky gecko feet, but its gripping quality can be switched on and off as needed.

Gecko's feet are able to stick to surfaces thanks to millions of microscopic hair-like projections known as setae. These temporarily bond with surfaces at a molecular level, due to Van der Waals forces. When the reptiles pull their feet forward, the bond is broken.

The INM team has replicated those setae in the form of manmade microscopic pillars. An array of those pillars on the end of a picking tool can bond with a variety of surfaces – both smooth and slightly rough – when an object needs to be picked up.

Once that object has been put in place, the picking tool doesn't have to be pulled away from it in order to let go. Instead, the adhesion is instantly switched off, by electronically altering the structure of the pillars. Unlike some other picking technologies, no adhesive is left behind on the object.

A testing rig equipped with the material (Photo: INM)

In its current form the system works both in and outside of a vacuum, attaining an adhesive force of over 1 Newton per square centimeter on smooth surfaces. What's more, it's still able to maintain that performance after 1,000 cycles.

That said, the researchers are now working on improving its adhesion, so it can be used to lift heavier objects. They're also looking at using triggers such as light, magnetic fields and temperature changes to turn that adhesion on and off.

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