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How Narrow Can a Meniscus Be?

2004; American Physical Society; Volume: 92; Issue: 8 Linguagem: Inglês

10.1103/physrevlett.92.085504

1092-0145

Joonkyung Jang, George C. Schatz, Mark A. Ratner,

Surface and Thin Film Phenomena

A water meniscus naturally forms in air between an atomic force microscope (AFM) tip and a substrate. This nanoscale meniscus produces a capillary force on the AFM, and also serves as a molecular transport channel in dip-pen nanolithography (DPN). A stable meniscus is a necessary condition for DPN and for the validity of the Kelvin equation commonly applied to AFM experiments. Lattice gas Monte Carlo simulations show that, due to thermal fluctuation, a stable meniscus has a lower limit in width. We find a minimum width of 5 molecular diameters (1.9 nm) when the tip becomes atomically sharp (terminated by a single atom).