Ice Nucleation Activity of Perfluorinated Organic Acids

• Main Authors: Ralph Schwidetzky (8921525), Yuling Sun (5688665), Janine Fröhlich-Nowoisky (3909490), Anna T. Kunert (3909484), Mischa Bonn (1235496), Konrad Meister (1355751)
• Format: Other Non-Article Part of Journal/Newspaper
• Language: unknown
• Published: 2021
• Subjects: Biophysics; Biochemistry; Medicine; Microbiology; Pharmacology; Ecology; Inorganic Chemistry; Environmental Sciences not elsewhere classified; Astronomical and Space Sciences not elsewhere classified; Biological Sciences not elsewhere classified; Chemical Sciences not elsewhere classified; Physical Sciences not elsewhere classified; carboxylic acid moieties; ice Nucleation Activity; PFA contamination; ice nucleation; transport pathways; cloud glaciation; PFOA correlates; High Arctic; perfluorooctanesulfonic acid; ice nucleating capabilities; ice nucleation capabilities; ice nucleation ability; Perfluorinated Organic Acids Perflu.; eight-carbon octanoic acid; deprotonated PFOA; perfluorooctanoic acid; chemical compounds; PFOA monolayer; hydroxyl groups; Arctic
• Online Access: https://doi.org/10.1021/acs.jpclett.1c00604.s001

Perfluorinated acids (PFAs) are widely used synthetic chemical compounds, highly resistant to environmental degradation. The widespread PFA contamination in remote regions such as the High Arctic implies currently not understood long-range atmospheric transport pathways. Here, we report that perfluorooctanoic acid (PFOA) initiates heterogeneous ice nucleation at temperatures as high as −16 °C. In contrast, the eight-carbon octanoic acid, perfluorooctanesulfonic acid, and deprotonated PFOA showed poor ice nucleating capabilities. The ice nucleation ability of PFOA correlates with the formation of a PFOA monolayer at the air–water interface, suggesting a mechanism in which the aligned hydroxyl groups of the carboxylic acid moieties provide a lattice matching to ice. The ice nucleation capabilities of fluorinated compounds like PFOA might be relevant for cloud glaciation in the atmosphere and the removal of these persistent pollutants by wet deposition.