Covalent Bonding of Functional Coatings on Conductive Materials: the Electrochemical Approach

Abstract

IntroductionThis chapter describes electrochemical approaches to achieve functional organic coatings of metals, carbon, and semiconductors, and discusses the advantages and limitations in the development of the emerging strategies, particularly focusing on examples of smart or stimuli-responsive polymer coatings. The various strategies are classified on the basis of the strength of the coating/metal interactions, starting with simply deposited coatings and then describing chemisorbed films.In the recent past, the coating of (semi)conductive inorganic materials such as metals (Au, Ag, Pt, Fe, Cu, etc.), carbon (glassy carbon, felt, microfibers, nanotubes, etc.), or semiconductors (doped Si, metal oxides, etc.) by an organic layer has attracted considerable attention because of the emergence of rapidly growing, very demanding fields such as nanotechnologies and biomedical sciences. Indeed, the wide versatility of organic and polymer chemistries allows to produce innovative coatings, such as stimuli-responsive coatings, that are of interest in the modification of surface properties of conductive materials. In particular, functional and/or responsive coatings are needed for applications such as solar cells, (bio)sensors, and biomedical implants. In addition, increasing concern about the environment tends to restrict the technologies and products to the greenest ones. Under these novel driving forces, efficient methods for the surface modification of conducting inorganic materials by polymer coatings are being developed.For the coating of conductive or semiconductive materials, one can take advantage of their electrochemical properties to control, master, and localize the coating and its adhesion to the substrate by applying an electrochemical treatment to the substrate under well-defined conditions.Electrochemical methods are easily applied and rapid, and are already widely used in industry. They can be often performed in aqueous media from readily available organic precursors and require relatively low energy. This technology thus appears really relevant in many cases in the creation of thin polymer films on (semi)conductors in possible greener conditions.