Durable PEDOT:PSS films obtained from modified water-based inks for electrochemical sensors

Printing of conducting polymer films from water-based inks is a powerful method that can facilitate the fabrication of various types of electrochemical sensors. This paper reports on the use of ethylene glycol and quaternary ammonium salts as additives to water-based poly(3,4-ethylenedioxythiophene) poly(styrenesulfonate) (PEDOT:PSS) inks in order to obtain conducting polymer films with improved adhesion to a carbon-based electrode substrate in aqueous environment. The modified PEDOT:PSS films deposited on glassy carbon were studied in aqueous solutions by cyclic voltammetry, electrochemical impedance spectroscopy, and potentiometry. It was found that PEDOT:PSS films modified with ethylene glycol and quaternary ammonium salts exhibit excellent adhesion to glassy carbon even after immersion in aqueous solutions for more than two months. The modified PEDOT:PSS films were electroactive, showed relatively fast ion transport properties, and were successfully applied as solid-contact material in lead(II)-selective electrodes.