(172d) PFAS Molecular Interactions and Organization in Solution and at Interfaces

Surface active per- and polyfluoroalkyl substances (PFAS) find niche applications because of their high chemical and thermal stability, high interfacial activity, and incompatibility with both water and hydrocarbons. However, PFAS accumulate in biota and humans, generating great concern. This calls for the replacement of PFAS from their various uses, and the capture of PFAS that have been released into the environment. Underlying the reformulation of PFAS-containing products and the PFAS sequestration are the inherent properties of surface-active molecules to interact and self-organize in response to their surroundings and/or external stimuli.

Analysis of complementary experimental and molecular dynamics results provides a detailed, atom/molecule-level description on how PFAS organize at fluid and solid interfaces, how they self-assemble in solution, how they interact with various compounds and surface functional groups, how all these modulate the PFAS mobility, and how the PFAS chemical structure impacts their behavior. We highlight results from our research on PFOA (perfluorooctanoate), PFBA (perfluorobutanoate) and GenX (2,3,3,3-tetrafluoro-2-(heptafluoropropoxy) propanoate) organization and dynamics at the air-water interface, self-assembly in aqueous solutions, binding to polymers in solution and to polymer networks, design of materials with optimal binding and selectivity, and regeneration of PFAS-adsorbent materials by disrupting the PFAS self-assembly.