Ultrathin platinum films on mica and the measurement of forces at the platinum/water interface

The chemical stoichiometry and structure of 2-10-nm-thick Pt films deposited on molecularly smooth mica have been characterized by Auger electron spectroscopy, transmission electron microscopy, electron diffractions, and direct-phase-detection microscopic interferometry. These analyses are correlated with electrical, optical, and electrochemical properties of the films with regard to their used in surface forces microbalance techniques. Large-area (1 cm/sup 2/), 4-nm-thick polycrystalline films are sufficiently conductive (sigma > 10/sup 4/ ohm/sup -1/ cm/sup -1/) and transparent (55% T at lambda = 550 nm) to allow measurement of forces between metallic phases. Preliminary measurements of electrostatic forces between two Pt films separated by a thin layer of water are presented.