Atomic force microscopy study of the texture of condensed phase domains in 1-monostearoylglycerol monolayers.

Atomic force microscopy (AFM) in friction mode is successfully used for probing the inner structure of condensed phase domains of 1-monostearoylglycerol (MSG) monolayers transferred from the air-water interface onto mica, glass, and silicon wafers by the Langmuir-Blodgett (LB) technique. The friction anisotropy reveals the same 7-fold domain substructure as observed at the air-water interface by Brewster angle microscopy (BAM). It is caused by differences in the tilt orientation of the molecules within the domain segments. After deposition ofthe monolayer, the main features of the condensed phase morphology, such as size, shape, and azimuthal tilt, are preserved independent of the solid substrate. The widths of the straight segment lines were found to be <100 nm. This result supports the idea that the segment boundaries of amphiphilic monoglycerol domains are low-energy lattice rows. Differences in the smoothness of the domain boundary at the air-water interface and on solid substrates can be caused by changes in the energetic conditions along the three-phase contact line.