ORIENTATIONAL ORDERING OF SURFACTANT MONOLAYERS ADSORBED AT THE AIR-WATER-INTERFACE - STRUCTURAL MODEL AND FIT TO NEUTRON REFLECTIVITY DATA

A new model for the structure of surfactant monolayers at interfaces i s proposed and its utility demonstrated by application to data from a recent neutron reflectometry experiment. From a least-squares fit of t he model to the reflectivity of a C-14TAB monolayer adsorbed at the ai r-water interface, the polar tilt angle of the hydrocarbon chains is e xtracted as a fitting parameter. Implications for the nature of orient ational ordering in adsorbed surfactant monolayers are noted and discu ssed.