3.6.1. Polishing and Cleaning 2663 3.6.2. Vacuum and Heat Treatments 2664 3.6.3. Carbon Electrode Activation 2665 3.7. Summary and Generalizations 2666 4. Advanced Carbon Electrode Materials 2666 4.1. Microfabricated Carbon Thin Films 2666 4.2. Boron-Doped Diamond for Electrochemistry 2668 4.3. Fibers and Nanotubes 2669 4.4. Carbon Composite Electrodes 2674 5. Carbon Surface Modification 2675 5.1. Diazonium Ion Reduction 2675 5.2. Thermal and Photochemical Modifications 2679 5.3. Amine and Carboxylate Oxidation 2680 5.4. Modification by “Click” Chemistry 2681 6. Synopsis and Outlook 2681 7. Acknowledgments 2682 8. References 2682

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Advanced carbon electrode materials for molecular electrochemistry.

Electrochemical reduction of a wide variety of aromatic diazonium salts on carbon electrodes (glassy carbon, highly oriented pyrolytic graphite) leads to the covalent attachment of the corresponding aromatic radicals The films thus deposited on glassy carbon surfaces require mechanical abrasion to be removed Cyclic voltammetry, X-ray photoelectron spectroscopy, polarization modulation IR reflection absorption spectroscopy, Auger spectroscopy, and Rutherford backscattering spectroscopy allow the characterization of the overlayer and an estimate of the surface coverage The latter can be controlled through diazonium concentration and electrolysis duration The mechanism of derivatization is discussed on the basis of the kinetic data obtained from cyclic voltammetry and preparative electrolysis This versatile method of surface modification may find applications in the field of carbon−epoxy composites as attested by the successful binding of grafted p-aminophenyl groups with epichlorhydrin

Covalent Modification of Carbon Surfaces by Aryl Radicals Generated from the Electrochemical Reduction of Diazonium Salts

Electrocatalysis at graphite and carbon nanotube modified electrodes: edge-plane sites and tube ends are the reactive sites

Electrografting refers to the electrochemical reaction that permits organic layers to be attached to solid conducting substrates. This definition can be extended to reactions involving an electron transfer between the substrate to be modified and the reagent, but also to examples where a reducing or oxidizing reagent is added to produce the reactive species. These methods are interesting as they provide a real bond between the surface and the organic layer. Electrografting applies to a variety of substrates including carbon, metals and their oxides, but also dielectrics such as polymers. Since the 1980s several methods have been developed, either by reduction or oxidation, and some of them have reached an industrial stage. This critical review describes the methods that are used for electrografting, their mechanism, the formation and growth of the layers as well as their applications (742 references).

Electrografting: a powerful method for surface modification

Surface characterization of electrochemically oxidized carbon fibers

Electrochemical oxidation of ω‐diamines on carbon fibers allows the bonding of these molecules to the carbon fibers. The conditions leading to this surface modification are described, and the influence of the different parameters is discussed. The structure of the bonded layer is studied by voltammetry, XPS, and SIMS. A mechanism is proposed which involves the coupling of a radical cation to the fiber. Toughness of carbon‐epoxy composites is improved when prepared from these modified fibers.

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Electrochemical Bonding of Amines to Carbon Fiber Surfaces Toward Improved Carbon‐Epoxy Composites

LE PROCEDE CONSISTE A POLARISER POSITIVEMENT LES FIBRES 3 PAR RAPPORT A UNE CATHODE 5, DANS UNE SOLUTION AQUEUSE 2 D'UN ELECTROLYTE CONSTITUE PAR UNE BASE FAIBLE AMINEE. ON FIXE AINSI A LA SURFACE DES FIBRES DES GROUPES AZOTES QUI AMELIORENT L'ADHERENCE DES FIBRES A LA RESINE DANS UN MATERIAU COMPOSITE FORME DE FIBRES DE CARBONE NOYEES DANS UNE MATRICE DE RESINE SYNTHETIQUE

Procede electrochimique de traitement de surface de fibres de carbone, fibre traitee par ce procede et materiau composite comportant de telles fibres

Electrochemical method of surface treating carbon; carbon, in particular carbon fibers, treated by the method, and composite material including such fibers

A method of electrochemically surface-treating carbon fibers, fibers treated by the method, and composite materials including such fibers. The method consists in positively polarizing fibers relative to a cathode in an aqueous solution of an electrolyte constituted by a weak amino base. Nitrogen-containing groups are thus fixed to the surface of the fibers thereby improving the adhesion of the fibers to the resin in a composite material constituted by carbon fibers embedded in a synthetic resin matrix.

Method of electrochemically surface treating carbon fibers, fibers treated by the method, and composite materials including such fibers

Le procede est du type dans lequel on met le carbone (3) en contact avec une solution (2) d'un compose amine dans un solvant dipolaire en le polarisant positivement par rapport a une cathode (5). The method is of the type wherein the carbon is placed (3) in contact with a solution (2) an amino compound in a dipolar solvent by biasing it positively with respect to a cathode (5). Selon l'invention, le solvant est un compose organique, de preference aprotique, a fort potentiel d'oxydation anodique et la solution est pratiquement exempte d'eau. According to the invention, the solvent is an organic compound, preferably aprotic, high potential anodic oxidation and the solution is substantially free of water.

Manuel Sanchez

Papers

Electrochemical Bonding of Amines to Carbon Fiber Surfaces Toward Improved Carbon‐Epoxy Composites

Procede electrochimique de traitement de surface de fibres de carbone, fibre traitee par ce procede et materiau composite comportant de telles fibres

Electrochemical method of surface treating carbon; carbon, in particular carbon fibers, treated by the method, and composite material including such fibers

Method of electrochemically surface treating carbon fibers, fibers treated by the method, and composite materials including such fibers

Electrochemical process for the treatment of carbon fibres, and fibres treated by this process