Analysis of air adsorptive on solid surfaces by AFM and XPS

Solid surfaces of HOPG, pure copper, chromium, zinc, copper and SUS304 steel were observed in ambient air with an a.c. non-contact mode of atomic force microscope(AFM). A type of film-like-domains (adsorptive) was detected on the above surfaces. The thickness of the adsorptive was about 1.2-2.4 nm in this case. The film-like-adsorptive was confirmed to be a liquid layer by the static contact-mode scanning, the measurement of the elasticity and viscosity images, and the detection of the condensation/evaporation phenomena when the relative humidity changed. The liquid layer is considered to be condensed water covered with organic contaminant.