International audienceCovalent surface modification of conductive, semiconductive, and insulating substrates with thin organic polymers films induced by redox activation of aryl diazonium salts in the presence of vinyl monomers has been investigated in acidic aqueous media. This new process, called diazonium-induced anchoring process (DIAP), is an efficient technique to impart covalent adhesion of polyvinyl coatings onto raw inorganic or organic surfaces without any conductivity requirement. Typically, aryl diazonium salts are reduced with iron powder to give surface-active aryl radicals leading (i) to the formation of a grafted polyphenylene-like film on the substrate surface and (ii) to the initiation of the radical polymerization of the vinylic monomer in solution. The resulting radical-terminated macromolecular chains formed in solution are then able to react with the polyphenylene primer layer to form a very homogeneous thin organic film on the surface. The final organic thin coating is strongly grafted on materials surfaces, as evidenced by its persistence after a long ultrasonic treatment in a good solvent of the polymer. We speculate this process is supported by the large concentration of aryl and hydrogen radicals formed when iron powder is added in the acidic aqueous solution. The thickness of the polymer film can be controlled as a function of time, typically a few minutes, and was measured between 10 and several hundred nanometers. Infrared reflection–absorption spectroscopy (IRRAS), X-ray photoelectron spectroscopy (XPS), scanning electron microscopy (SEM), high-resolution transmission electron microscopy (HRTEM), and contact angle measurements were used to characterize the surface modification of metals, glass, carbon nanotubes, or polytetrafluoroethylene (PTFE). This very simple and efficient grafting method provides a powerful tool for the covalent coating of organic or inorganic surfaces possessing complex geometrical shapes

Electrografting is a powerful and versatile technique for modifying and decorating conducting surfaces with organic matter. Mainly based on the electro-induced polymerization of dissolved electro-active monomers on metallic or semiconducting surfaces, it finds applications in various fields including biocompatibility, protection against corrosion, lubrication, soldering, functionalization, adhesion, and template chemistry. Starting from experimental observations, this Review highlights the mechanism of the formation of covalent metal-carbon bonds by electro-induced processes, together with major applications such as derivatization of conducting surfaces with biomolecules that can be used in biosensing, lubrication of low-level electrical contacts, reversible trapping of ionic waste on reactive electrografted surfaces as an alternative to ion-exchange resins, and localized modification of conducting surfaces, a one-step process providing submicrometer grafted areas and which is used in microelectronics.

The “ligand induced electroless plating (LIEP) process” is a simple process to obtain localized metal plating onto flexible polymers such as poly(ethylene terephtalate) and polyvinylidene fluoride sheets. This generic and cost‐effective process, efficient on any common polymer surface, is based on the covalent grafting by the GraftFast process of a thin chelating polymer film, such as poly(acrylic acid), which can complex copper ions. The entrapped copper ions are then chemically reduced in situ and the resulting Cu0 species act as a seed layer for the electroless copper growth which, thus, starts inside the host polymer. The present work focuses on the application of the LIEP process to the patterning of localized metallic tracks via two simple lithographic methods. The first is based on a standard photolithography process using a positive photoresist masking to prevent the covalent grafting of PAA in designated areas of the polymer substrate. In the second, the patterning is performed by direct printing of the mask with a commercial laser printer. In both cases, the mask was lifted off before the copper electroless plating step, which provides ecological benefits, since only the amount of copper necessary for the metallic patterning is used.

Nanotechnology aims to produce and manipulate well-defined structures at the nanoscale level with high accuracy. However, it has become quite clear in recent years that conventional ''top-down'' approaches are beset with perhaps insurmountable experimental difficulties owing to various physical effects that are not easily scalable, and most importantly, because of the cost issues associated with nanoscale fabrication processes. This state of affairs has led to great interest in the development of new methodologies based on bottom-up approaches. In this context, the DNA motif is of particular interest because of its unique intra-and intermolecular recognition properties. In particular, DNA has already been extensively used to construct nanostructures, [1,2] biomolecule/nanoparticle conjugates, and scaffolds for the assembly of nanoparticles. [3][4][5][6][7] The use of DNA for the assembly of devices can also be easily envisioned. Our goal is to use DNA not only as a positioning scaffold for nanodevices, but also as a support for the conducting element. For this purpose, we have developed a novel approach to metallize DNA molecules that have been previously deposited on a dry substrate in a typical nanodevice configuration. Several methods have been developed to metallize DNA scaffolds over the last 10 years, [8] and different metals have been used in the metallization process. One of the most common approaches involves ion-exchange on the DNA backbone for the deposition of silver [9,10] or copper.[11] Alternatively, positively charged gold nanoparticles have been deposited on DNA via electrostatic interactions with the negatively charged DNA backbone. [12,13] In another approach, Pt [14][15][16][17][18][19][20][21] and Pd [22][23][24][25][26][27] complexes have been extensively used for metallizing DNA based on the insertion of metal complexes between the DNA bases.Most DNA electroless-plating metallization techniques use a sequence of three main steps.[8] The first step consists of the binding of metal ions or metal complexes to DNA strands to create reactive metal sites. This step is usually called the activation step and is based either on exchanging ions into the DNA backbone, [9,10] or the insertion of metal complexes between the DNA bases. [14][15][16][17][18][19][20][21][22][23][24][25][26][27] In the second step, the reactive metal sites are usually treated with a reducing agent. This converts the metal ions or metal complexes into metal nanoclusters fixed onto the DNA strand. The third step of the metallization process consists of the autocatalytic growth of these affixed metal nanoclusters, which are now able to act as seeds because of the simultaneous presence of both metal-ions/metalcomplexes as well as reducing agents in the growth solution. Previous reports in the literature have illustrated the growth of metallic Pd nanowires by this approach. [20][21][22][23][24][25][26][27] However, the major drawback of this fabrication method is the fast kinetics of the growth reaction. Reducing agents dissolved...