Nanostructured Poly(Phenazine)/Fe2O3 nanoparticle film modified electrodes formed by electropolymerization in ethaline - Deep eutectic solvent. Microscopic and electrochemical characterization

Electropolymerization in ethaline deep eutectic solvent (DES) was carried out to prepare three different electroactive polymers on iron oxide nanoparticle modified glassy carbon electrode substrates: poly(neutral red), poly(methylene green), and poly(Nile blue). The electrochemical properties of the novel nanocomposites were studied by cyclic voltammetry, differential pulse voltammetry, and electrochemical impedance spectroscopy, and their morphologies were examined using scanning electron microscopy. Electrochemical characterization of the polymer films demonstrated similar voltammetric current response and impedance properties. Analysis of the cyclic voltammograms showed that the electrochemical processes at the polymer film coated electrodes are limited by surface reactions. Scanning electron microscopy images confirmed the results obtained by cyclic voltammetry and electrochemical impedance and showed more uniform and smooth polymer film surfaces produced in ethaline than those prepared in aqueous media, which can give important benefits for sensor and biosensor applications. Catalase enzyme was immobilized on the nanocomposite films, and the resulting biosensors were successfully used for the detection of H2O2, presenting low limits of detection with high repeatability and stability.