Preparation and characterization of novel p-acryloyloxybenzaldehyde copolymers bearing pyrene or fluorescein moieties. Interaction of fluorophore with some quenchers and silver nanoparticles

摘要

Two photopolymers, poly(vinyl acetate-co-p-acryloyloxybenzilideneiminepyrene) poly(VAc-co-AcrBzA)-Py and poly(vinyl acetate-co-p-acryloyloxybenzilideniminefluorescein) poly(VAc-co-AcrBzA)-Fl with pyrene and fluorescein in structure, have been prepared by chemical modification of the parent copolymer prior obtained through classical radical copolymerization. The structures of the polymers were characterized by FTIR, ~(1)H (~(13)C) NMR, UV, differential scanning calorimetry and thermogravimetric analysis, and gel permeation chromatography. The fluorescence properties of the photopolymers were investigated in dimethylformamide solutions containing various quenching agents (nitrobenzene, nitrophenol, p-nitrotoluene, picric acid, tetracyanoquinodimethane, Co~(2+), Hg~(2+), [UO_(2)]~(2+), NaOH, and HCl), the quenching efficiency varying in the next order: picric acid??TCNQ??p-nitrotoluene??nitrophenol. Quenching the fluorescence of fluoresceinimine occured only in acid medium (pH: 7.3–2.5) due to the protonated nitrogen, whereas with increasing basic pH (pH: 7.3–9.7) the fluorescence increased. Besides, fluorescence quenching or enhancement of fluorescence by silver nanoparticles (NPs) in situ photogenerated was investigated, our observations suggesting the role of polymer structure in stabilizing metal NPs in thin films.