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 C 8 /C 4 PF‐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.