COMPARISON OF ENANTIOMERIC AND RACEMIC MONOLAYERS OF N-STEAROYLSERINE METHYL-ESTER BY FLUORESCENCE MICROSCOPY

Monolayers of L-, D-, and racemic N-stearoylserine methyl ester (SSME) were examined using fluorescence microscopy and surface pressure isotherm measurements. Fluorescence microscopy reveals distinct differences in the condensed phase domain structures between the enantiomeric and racemic monolayers. The racemic SSME monolayer exhibits isotropic growth of the condensed phase, but with the formation of counterclockwise and clockwise hooks at the periphery of the domains. In contrast, the condensed phase of the L-SSME or D-SSME monolayers exhibits dendritic growth. The formation of condensed phase domains with the macroscopic curvature dependent upon the headgroup chirality is also observed. In the racemic monolayer, domains with both clockwise and counterclockwise curvature are observed; however, the L-SSME monolayer shows only domains with counterclockwise curvature and the D-SSME monolayer shows only domains with clockwise curvature. Fluorescence anisotropy is observable within the condensed phase at lower temperature, suggesting the presence of long-range tilt order.