Preparation of recyclable fluorescent electrospinning films and their application in distinguishing and quantitatively analyzing acid gases.

Acid gas, as a kind of polluting gas, poses a great threat to human health. Therefore, there is a need for a material that can detect it, and it is of great significance to find and deal with acid gas leakage in time. In this paper, the fluorescent micromolecule NAP‐OH, a naphthalimide derivative modified by morpholine, was introduced into polyurethane as an end‐capping agent, and the prepared nanometer fluorescent sensing material E‐NAP0.5/PU by electrospinning technology exhibited a sensitive ratiometric fluorescence response behavior to acid gas. The E‐NAP0.5/PU's specific surface area was 9.142 m2/g and its diameter was 200–400 nm. In 6 ppm HCl gas, TFA and FA gases, the response time of E‐NAP0.5/PU (deep orange red) films were 2, 20, and 40 s, and the colors were green, light green and light orange‐red, respectively. This showed that the membrane has great potential application in distinguishing acid gases. In addition, the E‐NAP0.5/PU changed from orange‐red to colorless within 30 s in SO2 gas with a concentration of 360 ppm. The detection limits of E‐NAP0.5/PU for HCl, TFA, FA and SO2 gases were 996 ppb (0–10 ppm), 660 ppb (0–8 ppm), 724 ppb (0–10 ppm) and 39 ppm (0–360 ppm), respectively. More importantly, E‐NAP0.5/PU could be reused multiple times. After five times of recovery, the E‐NAP0.5/PU film still recovered to its original fluorescence intensity, and kept a good response to acid. The 1H NMR and fluorescence spectra results indicated that the possible mechanism for acid gas detection of NAP‐OH was attributed to the protonation of morpholine group. To sum up, E‐NAP0.5/PU had a broad application prospect in acid gas detection. [ABSTRACT FROM AUTHOR]