Collaborative Research: Fluorinated Surfactants: Molecular Organization and Binding in Solution and on Surfaces

Surfactants are molecules that contain both a water-insoluble (or oil-soluble) component and a water-soluble component. Because of this property, surfactants are used in a wide range of applications such as detergents, emulsifiers, foaming agents, and dispersants. Fluorinated surfactants find a wide variety of industrial and consumer applications because of their high chemical and thermal stability and their unique abilities to render surfaces Teflon-like and to be immiscible with both water and hydrocarbons. Due to their stability, fluorinated surfactants also can be extremely resistant to degradation in the environment, bioaccumulate, and cause adverse health effects. Two fluorinated surfactants, perfluorooctanoic acid (PFOA) and perfluorooctane sulfonate (PFOS), have been phased out in the U.S. due to their toxicity and persistence in the environment. Several new fluorinated surfactants are being introduced for which very little information is available in the open literature about their properties. This collaborative research project combines experimental and computational methods to study the molecular organization of fluorinated surfactants in aqueous solutions. The studies will focus on quantifying how such emerging surfactants bind to other molecules or surfaces and how a fundamental understanding of such interactions can be utilized for the removal of fluorinated surfactants from the aquatic environment and biota. This research project has three objectives: (1) To understand nanoscale organization of well-defined fluorinated surfactants in aqueous solutions by using coordinated experimental characterization and molecular modeling efforts. The focus is on advancing computational capabilities to predict and match experimental results; (2) To establish and quantify key driving forces responsible for fluorinated surfactant molecular organization and interactions with other compounds (polymers, lipids, cyclodextrins) present in aqueous solutions and at liquid/solid interfaces. The focus is on emerging fluorinated surfactants and on interactions that are relevant to environmental and health concerns; and (3) To design and develop materials used in physical processes for the capture of fluorinated surfactants and their removal from aqueous media. The ability to predict molecular organization and interactions of fluorinated surfactants, and corresponding structure property relationships, can enable the rational design of new materials and methods for separating fluorinated surfactants. The results of this research should permit the in-silico evaluation of new chemical designs for potential replacements of fluorinated molecules in formulations and products. The research project serves as a training ground for graduate students to perform cutting edge research. The researchers also will engage undergraduate students in research and integrate the project with outreach and curriculum development activities. This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.