Marvelous Characteristics of Hydroxyl-Functionalized Azo-Dye Polymers for Electrocatalytic Sensing: An Informative Review

Hydroxyl-functionalized azo-dye monomers can be electropolymerized onto a supporting electrode surface, providing an electrocatalytic sensing feature due to their unique physicochemical and electrochemical properties. These polymers combine the versatile redox activity of azo groups with the improved conductivity and stability yielded by the conjugation of aromatic functional groups and hydroxyl functionalities. These properties synergistically enable the polymer film platforms to determine target analytes with greater accuracy, selectivity, and sensitivity than bare platforms, thereby facilitating electrocatalytic detection. Moreover, these polymer films have exhibited exceptional stability, consistent reproducibility, and remarkable resistance to fouling, making them well-suited for practical applications. This study evaluated the detection performance of platforms produced by the electropolymerization of hydroxyl-containing azo-dye monomers, and the underlying reasons for the observed electrocatalytic activity of these polymers were discussed using the extended Hückel charge and the Molecular Mechanics Force Field (MM2) calculations. Consequently, this review highlights the potential of hydroxyl-containing azo polymer-based electrodes as advanced electrochemical sensing platforms and provides excellent foresight in their use.