Capillary condensation in atomic scale friction: How water acts like a glue

We present atomic-scale friction force measurements that strongly suggest that the capillary condensation of water between a tungsten tip and a graphite surface leads to the formation of ice at room temperature. This phenomenon increases the friction force, introduces a short-term memory in the form of an elastic response against shearing, and allows us to write a temporary line of ice on a hydrophobic surface. Rearrangements of the condensate are shown to take place on a surprisingly slow time scale of seconds.