Copolymers of N-vinylcarbazole with acrylic acid, itaconic acid, and N-isopropylacrylamide: Synthesis, determination of monomer reactivity ratios, and electrochemical properties

Free radical copolymerizations of N-vinylcarbazole (NVCz) with acrylic acid (AA), itaconic acid (IA), and N-isopropylacrylamide (NIPAAm) at different feed ratios were conducted in 1,4-dioxane at 50C. The copolymers were characterized by UV and FT-IR spectroscopic techniques, viscosity, and glass transition temperature measurements. The monomer reactivity ratios were determined by application of the extended Kelen-Tudos method, which is one of the conventional linearization methods, and found to be rNVCz=0.29 and rNIPAAm=0.12, rNVCz=0.84 and rIA=0.12, rNVCz=0.86 and rAA=0.31 by UV, and rNVCz=0.32 and rNIPAAm=0.07 by FT-IR. Polymer-modified electrodes having electroactive, ionic, and hydrophobic properties were prepared by electro-oxidation using PNVCz, NVCz/NIPAAm, and NVCz/IA copolymers and tested as sensor electrodes to dopamine.