Investigating the Structure–Function Relationships of Fluorinated Interfaces for PFAS Capture and Electrochemically‐Mediated Release

Abstract Fluorinated materials are promising sorbents for the selective removal of per‐ and polyfluoroalkyl substances (PFAS) due to their unique fluorophilic interactions. However, there are gaps in the understanding of design principles toward fluorinated materials for optimized PFAS remediation. In this work, we vary the length of fluorinated side‐chains in copolymer‐functionalized electrodes to study their effect on electrochemically‐mediated PFAS capture and release. Molecular dynamics simulations and adsorption experiments reveal that binding is governed by the total amount of fluorophilic interactions rather than the length of the fluorinated side‐chain. Moreover, the length of the fluorinated side‐chain alters the polymer packing and porosity, which in turn affects PFAS capture and release. Simulations reveal that short‐chain PFAS percolate into the pores of the polymer matrix, while long‐chain PFAS aggregate on the surface, facilitating a faster desorption. Experiments show that desorption is enhanced upon applying potential, regenerating over 80% of the electrode and providing a reversible mechanism for the adsorption and release of PFAS. Additionally, the copolymer sorbents demosntrate selectivity between PFAS, achieving separation factors >190 for perfluorooctanoic acid (PFOA, 7 C–F) over perfluorobutanoic acid (PFBA, 3 C–F). This study provides insights into the design of functional fluorinated materials for electrochemical PFAS separations.