Conjugated polymers strongly adhering to electrically conductinos substrates

Poster (2003, May 16)

Archéométrie et orfèvrerie. À propos de l'expertise d'argenteries liégeoises

in Dumortier, Jean-Louis; George, Philippe (Eds.) Regards sur le XVIIe siècle. Feuillets de la Cathédrale de Liège (2003)

Full electrochemical synthesis of conducting polymer films chemically grafted to conducting surfaces

in Langmuir (2002), 18(13), 5222-5230

This paper reports on the full electrochemical synthesis of electrically conducting polymers chemically grafted to conducting surfaces (e.g., glassy carbon, stainless steel, nickel, gold). It is based on ... [more ▼]

This paper reports on the full electrochemical synthesis of electrically conducting polymers chemically grafted to conducting surfaces (e.g., glassy carbon, stainless steel, nickel, gold). It is based on new functional acrylate monomers, i.e., 3-(2-acryloyloxyethyl)thiophene and N-(2-acryloyloxyethyl)pyrrole, whose the synthesis is reported in this work. The polymerization process consists of two electrochemical steps. The first one is the cathodic electrografting of polyacrylate chains bearing a precursor of the conducting polymer in the ester group, either thiophene or pyrrole. In the second step, this precursor is polymerized under anodic polarization, in the presence or not of additional unsubstituted monomer in the electrochemical bath. Cyclic voltammetry was used to confirm that the two-component film is conducting and electrochemically active (reversible doping and dedoping). The chemical composition and the microscopic morphology of these composites were characterized by X-ray photoelectron spectroscopy and atomic force microscopy, respectively. [less ▲]

New silica based polymeric systems designed for the solid-liquid extraction of uranyl ions

in Journal of Materials Chemistry (2002), 12(1), 137-142

Electrochemical strategies for the strengthening of polymer – metal interfaces

in European Journal of Inorganic Chemistry (2001), 2001(5), 1097-1107

Polymers have been widely used for the protection of metals against corrosion and for improving the performance of structural adhesive joints. In this contribution, the weakness and short-term durability ... [more ▼]

Polymers have been widely used for the protection of metals against corrosion and for improving the performance of structural adhesive joints. In this contribution, the weakness and short-term durability of these polymer-metal interactions and some common approaches for alleviating this problem are briefly reviewed. Among the existing techniques, electrochemical processes offer the advantage of controlled interfacial reactions. Promising results have been reported by Strat-mann et al. and Le´cayon et al., who have emphasized the interest and opportunity to create strong chemical bonds between the organic coating and the metallic substrate. Their work is discussed in this review, along with results recently obtained in our group [less ▲]

Determination of the stability constants of uranyl/polymer complexes by differential pulse polarography

in Polymer (2001), 42(10), 4589-4596

Differential pulse polarography (DPP) allows for the determination of the stability constants (K) and the stoichiometry (n) for the complexation of the UO22+ ion by various monomers and the parent ... [more ▼]

Differential pulse polarography (DPP) allows for the determination of the stability constants (K) and the stoichiometry (n) for the complexation of the UO22+ ion by various monomers and the parent polymers. The experimental observation is the shift of the totally reversible reduction wave UO22++e- UO2+ toward more cathodic potentials when the complexing monomer or polymer is added to an uranyl nitrate aqueous solution. This shift is, however, much greater when the polymer is used rather than the monomer, in line with a higher stability of the complexes (Kpolymer>>Kmonomer). A theoretical stability scale of the polymers/UO22+ complexes was compared to an experimental one based on dynamic leaching tests. [less ▲]

New system for complexation of uranyl ions from liquid wastes of low-level activity: Polypyrrole doped with complexing polyanions

in Journal of Applied Polymer Science (2000), 77(6), 1230-1239

Polymer composites consisting of polypyrrole doped by uranyl complexing polyanions [i.e., poly(2-acrylamidoglycolic acid) and poly(2-acrylamido-2-methyl-1-propanesulfonic acid)] were electrochemically ... [more ▼]

Polymer composites consisting of polypyrrole doped by uranyl complexing polyanions [i.e., poly(2-acrylamidoglycolic acid) and poly(2-acrylamido-2-methyl-1-propanesulfonic acid)] were electrochemically synthesized. Bulk material and thin layers strongly adhering to inert supporting electrodes were prepared. These composites were used to precipitate uranyl ions from simulated radioactive wastes. Among different experimental techniques used for the analysis of uranium immobilized in the composites, the Rutherford backscattering of cu particles proved efficient in thin layers. Leaching tests confirmed the persistence of the uranium complexation in the solid composites. [less ▲]

Analyse PIXE sur un tableau de Cranach le Jeune. Les résultats et leur interprétation

in Art & Chimie. La couleur (2000)

The use of conducting polymers as cathodes for the electrochemical deposition of magnetic transition metal/rare alloys

in Journal of Materials Chemistry (2000), 10(3), 729-735

We report the electrodeposition of Cu and Ni in aqueous solutions together with the deposition of lanthanides (Gd, Sm, Dy, Tb) and amorphous magnetic alloys of lanthanides with transition metals (Fe, Co ... [more ▼]

We report the electrodeposition of Cu and Ni in aqueous solutions together with the deposition of lanthanides (Gd, Sm, Dy, Tb) and amorphous magnetic alloys of lanthanides with transition metals (Fe, Co) onto various polymer cathodes in formamide solutions. We used conducting polymers (polypyrrole, PPy; polyethylenedioxythiophene, PEDOT) sprayed on different substrates and in addition composite materials based on carbon black (CB) mixed either with polyethylene (PE) or with polycarbonate (PC). In the latter case, the conducting material is easily shaped out in various forms. When deposited on some of these substrates, the alloys appear as an interesting material for magneto-optic recording. The electrochemical process was used for the preparation of Gd/Co and Dy/Fe alloys for which the measured coercitive fields ranged from 250–300 Oe (Dy/Fe) to about 350 Oe (Gd/Fe). We demonstrated also the feasibility of an additional electrografting of a transparent protective layer of polyacrylonitrile (PAN) in order to avoid the corrosion of the alloys by the atmosphere. [less ▲]

Is the external beam PIXE method suitable for determining ancient silver artifact fineness?

in Nuclear Instruments & Methods in Physics Research Section B (2000), 161

In archeometry, the non-destructive characteristic of an analytical method is always very attractive. For most of techniques, besides the need of sampling, difficulties can originate from the shape and ... [more ▼]

In archeometry, the non-destructive characteristic of an analytical method is always very attractive. For most of techniques, besides the need of sampling, difficulties can originate from the shape and the size of the silver artifacts to be analyzed. The external PIXE method should be an answer to this problem but several questions are arising from the implementation of the technique to such a material. The aim of this paper is to specify the experimental procedure as to take into account several parameters, which could induce dramatic errors. Among them it can be pointed out the superficial enrichment in silver, arising from the dissolution of copper and copper oxide, the surface roughness effects, the great importance of the stability of the geometric conditions. The accuracy and the precision of the method are considered within the scope of the results obtained in ancient times by the cupellation with ashbone cupels. In addition. the process involved to obtain silver alloys has been studied in order to define its influence on the real fineness of the objects. (C) 2000 Elsevier Science B.V. All rights reserved. [less ▲]