Direct visualization of the dynamic behavior of a water meniscus by scanning electron microscopy

Scanning probe microscopic imaging can be complicated by the capillary force of water meniscus formed in air between the tip and the sample. Water menisci between a tungsten and Pt/C-coated mica and their dynamic behavior have been directly visualized by environmental scanning electron microscopy. Rapid scan secondary electron micrographs give information in the 100 nm range. We found that static models are not appropriate to describe to shape of a meniscus when the tip is moving across the sample. The surface structure and its properties influence the affinity of the meniscus thus causing a varying capillary force that may exhibit a vertical and a lateral component as well. Our experimental data indicate that the Kelvin equation also holds for microscopically small water menisci