Abstract
In the context of functional and hierarchical materials, electrode reactions coupled with one or more chemical reactions constitute the most powerful bottom-up process for the electrosynthesis of film components and their electrodeposition, enabling the localized functionalization of conductive surfaces using an electrical stimulus. In analogy with developmental biological processes, our group introduced the concept of morphogen-driven film buildup. In this approach, the gradient of a diffusing reactive molecule or ion (called a morphogen) is controlled by an electrical stimulus to locally induce a chemical process (solubility change, hydrolysis, complexation, covalent reaction) that induces a film assembly. One of the prominent advantages of this technique is the "conformal" nature of the deposits towards the electrode. This feature article presents the contributions made by our group and other researchers to develop strategies for the assembly of different polymer and nanoparticles/polymer hybrid films by using electrochemically generated reagents and/or catalysts. The main electrochemical-chemical approaches for conformal films are described in the case where: (i) the products are non-covalent aggregates that spontaneously precipitate on the electrode (film electrodeposition) or (ii) new chemical compounds are generated, which do not necessarily spontaneously precipitate and enable the formation of covalent or non-covalent films (film electrosynthesis). The applications of those electro-generated films will be described with a focus on charge storage/transport, (bio)sensing, and stimuli-responsive cargo delivery systems.