SYNTHESIS AND SENSING CHARACTERISTICS OF AB-TYPE BLOCK COPOLYMERS WITH FLUORESCENT PROBE

This article reports the synthesis through atom transfer radical polymerization (ATRP) of fluorescent block copolymers using the poly(ethylene oxide) containing terminal bromine atom as macroinitiator and hydrophilic block, while the hydrophobic block consists of n-butyl methacrylate and 2-methacryloyloxyethylcarbamoyloxymethylpyrene taken in various molar ratios. The characterization of the polymers was achieved by Fourier-transform infrared spectroscopy (FTIR), H-1-nuclear magnetic resonance (H-1 NMR), gel permeation chromatography (GPC), differential scanning calorimetry (DSC), thermogravimetric analysis and atomic force microscopy (AFM). Thus, the molecular weight and the molar composition of the block copolymers were estimated by H-1 NMR spectrometry, and were further confirmed by GPC analysis. Additionally, the fluorescence response of the pyrene-containing block copolymers towards certain metal ions (Pb2+, Co2+, Hg2+, Ni2+, UO22+, Zn2+), nitromethane and iodide anions in water was investigated, the study demonstrating that the synthesized block copolymers are viable candidates as fluorescent receptors for uranyl ions that can discriminate low concentrations of UO22+. The significant effect of iodide ions on the fluorescence intensity of the block copolymers in solution or in film state could be exploited in the development of `turn-off' or `turn-on' chemosensors for this type of analyte.