Engineers from Germany and Ukraine created a universal friction pad that creates high friction when in contact with different surfaces, including smooth and rough. It consists of a polymer membrane and ground coffee. In the normal state coffee behaves as a bulk body and with a membrane fills all depressions in the surface, and when pressure is applied the coffee into a hard body and does not shift the pad relative to the surface. Article published in the journal Advanced Materials Interfaces.
The problem of devices that create traction, is that the surface can be rough or smooth texture, for grip where you need different mechanisms. For example, in recent years, scientists have created a variety of artificial analogues of the pads of a Gecko with a very high adhesion to smooth surfaces, due to forces van der Waals forces, and already there is the production version of the manipulator. For rough surfaces, usually used pads with their irregularities. For example, NASA created according to this principle of climbing robots with multiple needles which can adjust its position under the small projections and recesses of the rocks.
The German-Ukrainian group of engineers, with the participation of Stanislav Humps (Stanislav Gorb) created adaptive contact area, able to adapt to the topography and including working with completely smooth surfaces. The basis for the engineers took the analogue of the effect of the phase transition observed in bulk solids. In the normal state bulk body behaves partly like a liquid, “into” without constraining forces. However, if the granular material to limit and to exert pressure, it will behave like a solid body, which is not so easily deform.