The interplay between adhesion and

An international team of researchers headed by the University of Zurich and with participation of Empa has developed a system that enables them to electrically switch back and forth between adhesion and stiction (static friction) of a water drop on a solid surface. The change in voltage is expressed macroscopically in an altered angle between the drop and the surface. This effect can be attributed to a change in surface properties on the nanometer scale. How can a gecko move across a ceiling upside down? Two mechanisms are responsible: adhesion via billions of extremely fine hairs on its feet, which enable it to stick to ceilings and walls. And as soon as the gecko moves, it relies on stiction. Any change of adhesion and stiction at macroscopic level is expressed on the nanometer scale through the change in the forces exerted between atoms and molecules. How a drop of water touches a honeycomb structure - An international team of researchers headed by Thomas Greber from the University of Zurich's Institute of Physics succeeded in changing the manner, in which a drop of liquid adheres to a surface by altering the electric voltage applied to a water drop.