Quartz-crystal microbalance studies of the slippage of solid and liquid krypton monolayers on metal(111) and C_(60) surfaces

摘要

We report a quartz-crystal microbalance (QCM) study of the nanotribology of solid and liquid krypton monolayers adsorbed on Cu(111), Ag(111), Ni(111), and C_(60) substrates at 77.4 K. We document the liquid-solid phase transition and compare the slip times of the krypton for the various substrates. The slip times for the solid krypton monolayers are longer than the slip times for liquid krypton monolayers on metal substrates and monolayer C_(60) films, as observed previously for krypton/Au(111). However, for bilayer C_(60) films, the jump in slip time at the liquid-solid phase transition is absent. We discuss the data within the context of recent molecular dynamics simulations and suggest several potential explanations for the experimental observations.