Binary and ternary deep eutectic solvent mixtures: Influence on methylene blue electropolymerisation

Abstract

Binary and ternary deep eutectic solvent (DES) mixtures based on choline chloride, with ethylene glycol, oxalic acid, urea and fructose, were used for the first time as media for the electropolymerisation of poly(methylene blue) (PMB) on glassy carbon electrodes (GCEs) and GCEs modified with multiwalled carbon nanotubes (MWCNTs). The influence of different parameters such as DES composition, the presence of MWCNTs and/or of perchlorate dopant, on the polymer film properties was evaluated. The polymer films electrodeposited in the different media were characterized by cyclic voltammetry and different voltammetric characteristics were observed depending on the electropolymerisation conditions. This knowledge was used to determine the best binary and ternary mixtures for polymer growth, with a view to electrochemical sensor applications. The PMB-based modified electrode with the best characteristics was tested for ascorbate sensing in order to demonstrate the usefulness of this platform.