Fluorinated Block Copolymer: An Important Sorbent Design Criteria for Effective PFOA Removal from Its Aqueous Solution

An important question remains unresolved, despite extensive studies on polymer-based sorbents for adsorbing poly and perfluoro alkyl substances (PFAS): How does the positioning of the fluorine-rich segment in polymer affect PFAS removal? Herein, we designed a linear, uncharged triblock copolymer incorporating a fluorinated moiety in the polymer backbone, which effectively removed perfluorooctanoic acid (PFOA) from water. In contrast, polymers without fluorogenic moiety or with it in the side chains showed significantly poorer PFOA removal. Our finding suggests that PFOA adsorption is more influenced by C-F···F-C interactions when the fluorinated segment is in the polymer backbone, not in the side chain.