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Brewster angle microscopy is used for investigations of nonequilibrium structures in 1-monopalmitoyl-rac-glycerol monolayers. The extent of branching of the condensed phase domains correlates with the supersaturation and thus with the compression rate of the monolayer. Dendritic growth is favored at intermediate compression rates, while tip splitting occurs at higher compression rates. The shape relaxation of unstable branched structures into nearly round equilibrium domains is shown by Brewster angle microscopy and described by a time development of the roundness. The optical anisotropy observed within the nonequilibrium structures allows the identification of the main growth direction of the dendrites with respect to the lattice directions.

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The influence of chirality on the structure of high- and low-temperature phases of monoglyceride monolayers has been studied by Brewster angle microscopy (BAM) and grazing incidence X-ray diffraction (GID). While there is no effect of the chiral center of monopalmitoylglycerol on the monolayer structure at 20 °C, an influence of chirality has been found for monostearoylglycerol at 5 °C. At low temperature the latter compound has an oblique lattice of the molecule chains at all investigated surface pressures, while the racemic mixture exhibits a rectangular structure. Additionally, it can clearly be visualized by BAM that the racemic mixture exhibits a phase transition between 6 and 12 mN/m at 5 °C characterized by a change of the tilt azimuth. By using GID, this transition could be identified as a change of the azimuthal tilt angle from a nearest neighbor (NN) direction to a next nearest neighbor direction (NNN).