1. van't Hoff Institute for Molecular Sciences, University of Amsterdam, P.O. Box 94157, 1090 GD Amsterdam (The Netherlands);2. Institute of Physics, University of Amsterdam, P.O. Box 94485, 1090 GL Amsterdam (The Netherlands)
Abstract:
The area of contact between two objects was detected by using the strong enhancement of the fluorescence of rigidochromic probe molecules attached to one of the surfaces. Confinement of the molecules suppresses nonradiative decay and turns on the fluorescence. The approach is demonstrated by imaging of the contact area of a plastic sphere in contact with a flat glass surface. Our results agree excellently with the prediction of Hertz’s classical theory based on elastic deformation.