Adhered cantilevers: A new method to measure dispersion forces between rough surfaces at short distances

Dispersion forces start to play an important role when the bodies are separated by the distances smaller than 100 nm. Such small gaps characterize modern nano- or microelectromechanical systems. Although the forces were reliably measured and compared to the theory in the range of 30-100 nm, severe problems appear at distances shorter than 30nm due to jump-to-contact instability. In this paper we propose a new measurement method, which does not suffer the short-distance instability. The method is based on the shape of an adhered cantilever that is sensitive to the forces acting near the adhered end. Two values are measured simultaneously: the dispersion pressure at minimal separation (close to contact) and the adhesion energy. Roughness of interacting surfaces plays a crucial role. We discuss possible realization of this experiment and propose the choice of optimal parameters.