Study of long-range tilt orientation in fatty acid monolayers by dynamic scanning force microscopy

Segments in the liquid condensed (LC) domains of stearic acid, induced by long-range tilt orientation, were visualized on solid substrates by applying scanning force microscopy (SFM) using the force modulation mode (FMM). To understand the image contrast, a model based on the asymmetric apex of the SFM tip and the tilted phase of the molecules on the solid substrate after film transfer is presented. As a result, the apparent local elasticity is found to vary for molecules having the same tilt angle but different azimuthal angles. The observed textures are in good agreement with the theoretically predicted ones.