Fluorescent nonwoven fabric with synergistic dual fluorescence emission for visible and selective ammonia gas detection

Although ammonia gas plays an important role in the modern society, it poses a serious threat to human beings. Therefore, an effective ammonia gas-detection method with features like convenient operation, rapid response, excellent selectivity, and high sensitivity is urgently needed. Herein, a fluorescent polyethylene/polypropylene nonwoven fabric with co-existing pyrene units and –SO3H groups was fabricated by radiation-induced graft polymerization (RIGP), followed by a two-step chemical modification. The prepared fluorescent nonwoven fabric displays a rare dual emission and has a related high quantum yield of 32.65%. Besides, a remarkable synergistic interaction between the pyrene units and –SO3H groups causes the prepared fluorescent nonwoven fabric to exhibit superior ammonia detection abilities. Pyrene units act as efficient luminescence centers and therefore significantly enhance the sensitivity of ammonia detection. The –SO3H groups act as exclusive recognition centers and improve the selectivity for ammonia. Interestingly, the changes in the fluorescence intensity of the dual emission display a reverse trend upon interaction with the ammonia gas, causing the fluorescence color to change from purple to blue, thus achieving the visible detection of ammonia gas. Additionally, the as-prepared fluorescent nonwoven fabric can detect ammonia with the advantages of rapid response (in 5 s), excellent selectivity, high sensitivity, low detection limit (approximately 0.6 ppm), and good reproducibility and reusability.