AFM measurements of hydrophobic forces between a polyethylene sphere and silanated silica plates — the significance of surface roughness

The existence of non-DLVO attractive interactions between hydrophobic surfaces, frequently much stronger than van der Waals forces and with a much longer range, has been reported in the literature [1-3]. Variation in the magnitude and range of these attractive forces is considerable and not well explained. Little attention has been given to the effect of surface roughness, which should be of considerable importance.