Equilibrium surface tension of pure component solutions can be well described by the Gibbs adsorption equation in combination with an adsorption isotherm. But if the solution is a mixture of two components and has a tendency of interactions, the situation is very different. Our preliminary results indicate that the surface tension of a mixture of a biomolecule and its ligand is not the simple addition of the effect of each component. The dependence of the mixture's dynamic and equilibrium surface tensions on the component concentration can reveal the interaction of a biomolecule with its ligand, and the binding sites on the ligand or the biomolecule can be determined. The objective of this project is to detect the interaction characteristics of the molecules from surface tension study, and develop a new model for describing the surface tension of the mixture of interacting molecules. Some of the past and current research in this area include:
