Optimal roughness for minimal adhesion, Applied Physics Letters 91, 043107 (2007), D.-L. Liu, J. Martin, and N.A. Burnham
ABSTRACT Roughness has a significant affect on adhesion. The authors used a single-asperity model to describe a smooth tip in contact with a rough surface and predicted that an optimal size of asperity yields a minimum of adhesion. Experimentally, adhesive forces on silicon wafers with varying roughness were measured using atomic-force-microscopy cantilevers with varying tip radii. It was found that minima do exist, and for all tip radii, the adhesion falls significantly for roughness greater than 1--2 nm and drops at higher roughness for larger tips. This work should help minimize stiction in microelectromechanical systems and progress the understanding of nanoscale-contact mechanics.
