Dual responsive spiropyran-ended poly(N-vinyl caprolactam) for reversible complexation with metal ions

• DOI: 10.1007/s10965-019-1747-z
• Publication Date: 2019-03-13T14:03:31Z
• Authors: Zhouxiaoshuang Yang; Feng Wang; Hui Liu
• Keywords: Spiropyran; Caprolactam; Merocyanine; Atom-transfer radical-polymerization; Naked eye

With the spiropyran-containing compound as the initiator, dual responsive spiropyran-ended poly(N-vinyl caprolactam) (SP-PNVCL) was synthesized by atom transfer radical polymerization. The structure of the resulting polymer was characterized by 1H NMR and gel permeation chromatography, and the polymer had both reversible light-responsive and thermo-sensitive behaviors. Metal ions could be bound between merocyanine formed by photoisomerization of spiropyran and the amino group of N-vinyl caprolactam unit through synergetic coordination. The complexation of SP-PNVCL with several metal ions was investigated by UV-Vis absorption spectroscopy, and it was found that SP-PNVCL might be used as a potential recognition probe for Fe2+, accompanied by obvious color change from colorless to brown by naked eye. The detection limit and photo-reversible recyclable behaviors of SP-PNVCL for Fe2+ were also investigated in details. The kind of spiropyran-ended poly(N-vinyl caprolactam) had great application potential in environment protection and biological area.