A Waterborne Polyurethane‐Based Dye with Green Fluorescence Excited by Visible Light

Abstract A waterborne aminofluorescein polyurethane‐based dye (AF‐WPU) with green fluorescence excited by visible light was synthesized by anchoring aminofluorescein (AF) to waterborne polyurethane chains. The structural characteristics of AF‐WPU was confirmed by means of 1 H‐NMR, FT‐IR and UV‐vis absorption. Compared with AF, there is a hypsochromic shift, and a new absorption peak generating in the UV‐vis spectra of AF‐WPU. Meanwhile, AF‐WPU emited excellent fluorescence. The fluorescence intensity of AF‐WPU increased five times at the same concentration. It is found that the fluorescence intensities of AF‐WPU decreaseed with increased temperature, and increased first and then decreased with increasing concentration. The fluorescence of AF‐WPU is very stable and insensitive to quenching agents. Moreover, AF‐WPU which excited by visible light is less phototoxic to health, and has a broad prospect in practical applications.