Electrografting of Aryl Diazonium Monolayers onto ITO to Generate Hybrid and Structural Silica/Polypyrrole Coatings

Compositing and hybridizing compounds is a generally accepted route to making new materials that perform better than the individual components taken separately. Herein, we describe a new electrochemical route for constructing hybrid materials from Polypyrrole (PPy). In this context, thin films of silica layer (Si) deposited by electro-assisted on a flexible ITO (f-ITO) surface modified by diazonium salt (f-ITO-NH2) were covered with an adhesive layer of polypyrroles. Deposition periods ranging from 20 to 45 seconds produce more electroactive silica layers. The electrochemical method confirmed the growth of a silica layer on the surface of the f-ITO-NH2 electrode. The different flexible electrodes were characterized by XPS, by electrochemical and scanning electron microscopy (SEM), which showed the central role of the diazonium chemical interface in the development of PPy on the silica layer. According to cyclic voltammetric studies, altering the f-ITO surface with diazonium salts produces PPy-Si polymers with more conductivity than a comparable coating without integrated treatment. This work demonstrates the power of a subtle combination of diazonium coupling agents on f-ITO, silica layer, and conductive polymers (f-ITO-NH2-Si-PPy) to design high-performance electrochemical materials.