Vapor-Phase Detection of Perfluoroalkyl Acids using Amplifying Fluorescent Polymers

Perfluoroalkyl acids are a subclass of persistent toxic per- and polyfluoroalkyl substances (PFAS) whose volatility enables airborne exposure pathways that remain largely unmonitored. Therefore, suitable technologies are urgently needed for real-time monitoring of PFAS acids in the vapor phase. Herein, we report a new platform for selective vapor-phase detection of volatile perfluoroalkyl acids using amplifying fluorescent polymers. The designs incorporate highly fluorinated moieties to create a fluorous microenvironment that enhances selectivity and pyridine-based selectors that react with volatile PFAS acids through proton-transfer reactions. Ratiometric fluorescence detection was employed in sensing experiments, and polymer thin films exhibited rapid responses (<5 s) to PFAS acids vapor exposure, with the induced signal persisting for more than 15 min. The polymer C₈/C₄PF-Py emerged as the most sensitive material, exhibiting vapor-phase detection limits of 47.8 ppm, 2.38 ppm, and 450 ppb for TFA, PFBA, and GenX, respectively. This work establishes a versatile, rapid, and selective platform for vapor-phase detection of PFAS acids. The materials can be coated on a variety of surfaces, and their fluorescence changes can be easily monitored, thereby reducing expensive instrumentation dependence and laboratory testing, providing a practical pathway toward routine monitoring and regulation of airborne PFAS acids.