Foams serve a number of applications. One use critical to the Navy is aqueous film forming foam (AFFF), used for fire protection in a number of military and civilian applications. AFFF coats a liquid hydrocarbon fuel with a layer of foam, which acts as a thermal barrier to inhibit and eventually extinguish combustion. The ability of AFFF to produce foam, as well as the aqueous layer covering the less dense hydrocarbon liquid, is made possible by using surfactants to reduce surface tension. In addition to water, AFFF formulations typically contain hydrocarbon surfactants, fluorocarbons surfactants, as well as other additives. Generating renewed interest in AFFF are recent environmental concerns about the fate of some PFAS (perfluoro and polyfluoro substances) containing fluorocarbon surfactants used in AFFF. Investigating the behavior of novel types of surfactants to determine their applicability to fire suppression will help identify new, environmentally-friendly alternatives, including PFAS-free alternative surfactants and biologically-derived materials.

This research focuses on the search for firefighting foams giving performance comparable to AFFF while being environmentally benign. Scientific background needed to accomplish these goals includes understanding the relationships among the chemical structure of a surfactant, physical and chemical properties of foaming agents, and their performance in fire suppression. Specific scientific issues include (1) characterizing how composition and molecular structure of surfactants and fuels influences oleophobicity, (2) Langmuir-Blodgette film structure, (3) understanding synergism between different surfactants, (4) understanding the role of micelles in transport of surfactants across an interface, (5) studying the influence of fuel on stability of foams.