Friction anisotropy and asymmetry related to the molecular tilt azimuth ina monolayer of 1-monopalmytoyl-rac-glycerol

The molecular tilt azimuth in domains of a condensed phase in monolayers of 1-monopalmytoyl-racglycerol at the air/water interface exhibits a regular star texture. Lateral-force microscopy has been used to investigate the fri ction behavior of a monolayer that has been transferred onto a silicon subs trate. The condensed domains revealed strong friction anisotropies and asym metries. The angular dependence of these properties correlates well with th e tilt azimuth of the alkyl tails in the monolayer.