Gady B, Schleef D, Reifenberger R, Rimai D, and DeMejo LP.
Dept. of Phys., Purdue Univ., West Lafayette, IN, USA.
Identification of electrostatic and van der Waals interaction forces between a micrometer-size sphere and a flat substrate.
Physical Review B-Condensed Matter, vol.53, no.12, 15 March 1996, pp.8065-70. Publisher: APS through AIP, USA.
The interaction force gradient between a micron-size polystyrene sphere and an atomically flat highly oriented pyrolytic graphite substrate has been analyzed as a function of surface-to-surface separation distance z/sub o/ using an oscillating cantilever technique. The interaction force gradient was found to have two contributions. For z/sub 0/>or=30 nm, an electrostatic force due to charges trapped on the polystyrene sphere dominates. For z/sub 0/