Aggregation-induced emission nanofiber as a dual sensor for aromatic amine and acid vapor

Abstract

Two cyano-substituted vinylacridine derivatives linked with N-dodecyl-L-phenylalaninamide through succinyl (PC2VA) and glutaryl (PC3VA) groups were synthesized and were found to exhibit aggregation-induced emission properties. These two compounds could form gels in some solvents at low concentrations and exhibit fluorescence enhancement during gelation. The gelation abilities and microstructure intermolecular interactions of these compounds were different, although their molecular structures varied by only one methylene group. Moreover, a uniform fibrous film that could be used as an effective dual sensor on glass plates was prepared using PC2VA wet gels to quantitatively detect aromatic amine and volatile acid vapors caused by the low HOMO energy level of the fluorophore and the existence of the acridine moiety as an acid binding site. The response times and detection limits (DL) for the vapors are short and low, respectively. The DL of aniline reaches 1.3 μg m⁻³ because an amplifying fluorescence quenching exists within the long nanofibers induced by efficient exciton diffusion along the π–π stacking direction. Moreover, the DL for trifluoroacetic acid is low and determined to be 2.3 mg m⁻³.