A Quantitatively Accurate Theory To Predict Adsorbed Configurations of Linear Surfactants on Polar Surfaces

Surfactant molecules are known to adsorb onto polar surfaces in different morphologies. The ability to predict the adsorption morphologies is important for tuning interfacial properties via surfactant adsorption. Linear surfactant molecules may adsorb in a stripe-like configuration (stripes) with their molecular axes parallel to the surface and to one another or as a self-assembled monolayer (SAM) with the molecular axes perpendicular to the surface. By comparing the associated energetics of these configurations, the favorable one can be predicted. Based on this concept, we have developed a theoretical model with no fitting parameters for describing adsorbed configurations of linear surfactant molecules on polar surfaces. The predictions of the model are in excellent agreement with the results of molecular simulations. In addition, our model explains observations of different kinetic pathways for SAM formation, which have been reported in experiments.