A naked‐eye, highly sensitive and recyclable cliometric acid–base indicator based on xylenol orange functionalized polyvinyl alcohol fiber

Abstract In this work, a novel xylenol orange functionalized polyvinyl alcohol fiber (PVAF‐XO) was designed and prepared through a simple one‐step reaction and characterized using elemental analysis, x‐ray powder diffraction (XRD), Fourier‐transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM). The prepared PVAF‐XO exhibits excellent sensitivity to acid and base solutions, featuring a remarkable visual color change from pale yellow to orange red (acid) or purple (base) within 1 s. It is shown that PVAF‐XO has the advantages of excellent acid–base double response color change, low naked‐eye detection limit (8 × 10 −4 mol/L), excellent reusability (>500 times), high photostability (90 days) and concentrated acid–base stability, etc. This research is an important exploration for the application of functionalized polyvinyl alcohol fibers to pollution prevention.