Eu3+ ions grafted polyacrylonitrile nanofibers possessing enhanced fluorescence performance by introducing benzoic acid as assistant ligand

Eu³⁺ ions were grafted onto the surface of electrospun polyacrylonitrile (PAN) nanofibers through coordination effect between CN groups on PAN nanofibers and Eu³⁺ ions, and benzoic acid (BA) was introduced as an assistant ligand. The impacts of concentrations of Eu³⁺ ions and BA, and reaction time on the properties of final products were investigated. The results reveal that Eu³⁺ ions can be successfully grafted onto PAN nanofibers, but the fluorescence intensity of the obtained PAN@Eu³⁺ nanofibers is very weak. After BA is introduced as the assistant ligand, the fluorescence intensity of the obtained PAN@(Eu³⁺/BA) nanofibers is greatly stronger than that of PAN@Eu³⁺ nanofibers, and meanwhile, concentration quenching effect of Eu³⁺ ions can be effectively restrained. Furthermore, the superior structure of PAN@(Eu³⁺/BA) nanofibers not only brings the effective utilization of precious elemental europium, but also guarantees high mechanical strength.