Guy Deniau

Guy Deniau
Atomic Energy and Alternative Energies Commission | CEA · Institut rayonnement matière de Saclay (IRAMIS)

PhD

About

59
Publications
3,155
Reads
How we measure 'reads'
A 'read' is counted each time someone views a publication summary (such as the title, abstract, and list of authors), clicks on a figure, or views or downloads the full-text. Learn more
1,415
Citations

Publications

Publications (59)
Article
Full-text available
In this work, a multifunctional non-toxic chromium free treatment is proposed. Hexavalent chromium, largely used for anticorrosion surface treatments of aluminum alloys in aeronautics, will soon be completely banned due to its high toxicity (European REACH regulation) and new solutions are required. Here, in a first step, a polymeric film was graft...
Conference Paper
Full-text available
The BTEX (benzene, toluene, ethylbenzene and xylene) volatile organic compounds constitute an important class of indoor air pollutants. Human exposure to these compounds can cause serious damages on human health due to their carcinogenic nature. Therefore, it is a priority to detect such pollutants. Carbon nanotubes (CNTs) have received considerabl...
Patent
Full-text available
This invention relates to a method for preparing an organic film at the surface of a solid support, with a step of contacting said surface with a liquid solution including (i) at least one protic solvent, (ii) at least one adhesion primer, under non-electrochemical conditions, and allowing the formation of radical entities based on the adhesion pri...
Article
Based on the literature, the reduction of diazonium salts (either by electrochemistry, photochemistry or chemistry) leads to a covalently grafted polyphenyl-like coating. We describe here a new diazonium-based redox process that leads to thick and strongly adherent coatings similar to the ones obtained by electroreduction, but without any electroch...
Article
The spontaneous reaction of diazonium salts on various substrates has been widely employed since it consists of a simple immersion of the substrate in the diazonium salt solution. As electrochemical processes involving the same diazonium salts, the spontaneous grafting is assumed to give covalently poly(phenylene)-like bonded films. Resistance to s...
Conference Paper
This work reports the design of a resistive gas sensor based on 2D mats of multi-walled carbon nanotubes (MWCNT). The sensor sensitivity was optimised using chlorine by tuning both MWCNT network morphology and MWCNT electronic properties. Raw CNT were compared with annealed CNT. Besides, with the aim to enhance the sensor sensitivity and selectivit...
Conference Paper
This document aims at presenting and explaining the mechanism of a simple "green process", called Graftfast (c), recently developed in order to graft polymer films onto any type of materials. This process is of great interest as it works in a short one step reaction at room temperature, atmospheric pressure in water. Particularly since this method...
Article
Full-text available
The grafting of biocompatible poly(hydroxyethyl) methacrylate (PHEMA) by a very simple method onto titanium dioxide nanoparticles is reported. The selected grafting process is based on the chemical reduction of diazonium salts by reducing agents in presence of the vinylic monomer. As previously demonstrated on flat surfaces, it leads to strongly gr...
Article
In this work we present two techniques that provide localized functionalization of the surface of materials. Both lead to localized grafted thin organic films (10–200nm). The localization is brought by a chemical lift-off process, which relies on patterned weakly bonded films as sacrificial layers, combined with electrochemical (SEEP) or chemical (...
Article
In this work, we present an efficient grafting of functional polymers onto multi-walled carbon nanotubes using a simple and versatile chemical process carried out in open air and in aqueous media. The method involves in situ reduction of substituted (–COOH, –NH2, –F…) aryl diazonium salts which yields poly(phenylene)-like coatings covalently grafte...
Article
As recently reported, the Graftfast process is a grafting method that provides covalently grafted polymer films. It relies on the chemical reduction of diazonium salts by reducing agents in absence or presence of a vinylic monomer. Contrary to electroinduced methods delivering strongly grafted and stable polymer films such as cathodic electrografti...
Article
As recently reported, the SEEP process (surface electroinitiated emulsion polymerization) is a new grafting method that provides covalently grafted polymer films on conducting or semiconducting surfaces by radical polymerization in aqueous dispersed media. It relies on cathodic electroinitiation, which creates radical species able to start a radica...
Article
The grafting of poly n-butyl methacrylate (PBuMA) on gold surface has been achieved via cathodic electrografting and by surface-initiated atom transfer radical polymerization (SI-ATRP). Both polymerizations, that are classically referred to as “grafting from” methods, can be carried out in similar conditions for the synthesis of grafted organic coa...
Article
Full-text available
Diazonium salts coupled with vinylic monomers were able to functionalize carpets of carbon nanotubes by electro-activation in aqueous media. Hence, nano-sized carbon surfaces were shown to react with active radical species in solution through a new covalent grafting process called Surface Electroinitiated Emulsion Polymerization (SEEP), where diazo...
Poster
Full-text available
Water based Diazonium Induced Anchoring Process (DIAP) for Aligned MWCNT Functionalization and Its Polymer Composites
Article
Covalent 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...
Article
An adherent polymer film based on a composite of polyacrylonitrile/multiwall carbon nanotubes (PAN/MWNTs) have been elaborated on a copper substrate. The first layer is an electrografted PAN brush on which of a subsequent layer of PAN/carbon nanotubes composite has been deposited by simple dipping from solution in dimethylformamide (DMF). MWNTs hav...
Article
The surface electroinitiated emulsion polymerization (SEEP) protocol, described here for the first time, combines the advantages of the electrografting process, which delivers thin organic coatings chemically bonded to conducting surfaces, with polymerization in emulsion, which allows synthesizing hydrophobic polymers in aqueous solutions. From the...
Article
We report for the first time on grafting of poly(n-methyl methacrylate), (PMMA), and polystyrene (PS) brushes by ATRP from the surface of aligned multiwalled carbon nanotubes (MWCNT) which were electrochemically treated with brominated aryl groups based on diazonium salts. The polymer brushes formed amorphous coatings, as evidenced by high-resoluti...
Data
We report for the first time on grafting of poly(n-methyl methacrylate), (PMMA), and polystyrene (PS) brushes by ATRP from the surface of aligned multiwalled carbon nanotubes (MWCNT) which were electrochemically treated with brominated aryl groups based on diazonium salts. The polymer brushes formed amorphous coatings, as evidenced by high-resoluti...
Article
This paper reports functionalization of carbon nanotubes (CNTs) via cathodic electropolymerization. Indeed, this technique ensures good control of the grafted polymer (PMAN in our study) on the surface of the substrates (CNTs). The study was done both on single-wall nanotubes (SWNTs) and multi-wall nanotubes (MWNTs) following two distinct approache...
Article
2-Butenenitrile belongs to the large family of electron deficient vinylic monomers that usually form 100 to 500nm thick grafted polymer films by electroreduction. However, 2-butenenitrile exhibits a slightly acidic hydrogen atom on its CH3 group that inhibits the anionic polymerization usually observed with ‘classical’ organic monomers such as its...
Article
In this work, we study the simultaneous polymerization of vinylic monomers initiated via the electrografting of suited precursors on metallic substrates. The outcome of this work is to be able to obtain, in one step, new modified substrates with various surface properties brought by the combination of both polymers. For that purpose, two different...
Article
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,...
Article
In this work the chemical transformations induced by protons and α beams (1017 ion cm−2) at the surface of polycrystalline iron are analysed by X-ray Photoemission Spectroscopy (XPS). Spectroscopic changes for both incident particles are globally different. We show that helium particles contribute to etch away the oxygen leaving the iron surface in...
Article
In this work, we studied the electrochemical formation of polymethacrylonitrile by cathodic polarization in an anhydrous organic medium, at two different working potentials either side of the potential of the high concentration reduction pre-peak. In both cases, the polymer formed in solution and the so-called grafted polymer were obtained. A detai...
Article
The electropolymerization of methacrylonitrile has been performed under voltammetric conditions on a rotating disk electrode (RDE) spinning at high angular rotation rate (ω=10000 rpm) in anhydrous acetonitrile. The analysis of the electrode surface by X-ray photoelectron spectroscopy (XPS) and ellipsometry reveals that a grafted film of polymethacr...
Article
In this work, the chemical transformations induced by 5 keV protons (106 ion cm−2) at the surface of 0.4 μm polyacrylonitrile and polymethacrylonitrile films are analysed by XPS and IRRAS. Spectroscopic changes in both the polymers are globally similar, the most significant feature being a lower relative concentration of nitrogen with respect to ca...
Article
The interaction between a nickel substrate and thin polyacrylonitrile films is studied by electron-induced x-ray emission spectroscopy (EXES). The analysis of the metal 3d distribution at the interface suggests that a direct interaction takes place between the metallic sites and the monomer molecules when the metal is cathodically polarized. The ex...
Article
Full-text available
2-Methyl 2-propenenitrile (methacrylonitrile) and 2-butenenitrile (crotononitrile) are vinylic molecules which differ only in the position of a methyl group on the double bond. By combining gas chromatography coupled to chemical ionization mass spectrometry, steric exclusion chromatography and infra-red spectroscopy, along with quantum chemistry ba...
Article
The application of anodic or cathodic polarization to a highly concentrated solution of 4-vinylpyridine leads to the formation of a polymer film grafted on the metallic electrode. The polymer structure, studied by IRRAS and XPS spectroscopies depends on the nature of polarization.
Article
Polyacrylonitrile films (0.1 μm) were irradiated with 3 keV protons (1016 ion · cm−2) and exposed to air (dry and humid). The chemical transformations were characterised by XPS and IRRAS. A significant depletion of the N-containing species in the first layers and a general increase in unsaturated structures are observed. After exposure to air for o...
Article
According to Mertens et al., polyacrylonitrile (PAN) is selectively electrografted onto nickel at less cathodic of two reduction potentials of acrylonitrile (AN) as a result of the formation of (AN) radicals which are firmly linked to cathode and propagate radical polymerization of AN. Anionic mechanisms can be rejected on the basis of 3 new experi...
Article
The cathodic electropolymerization of methacrylonitrile was followed with an electrochemical quartz crystal microbalance used in combination with other classical techniques such as cyclic voltammetry, chronoamperometry and impedance spectroscopy. The quartz microbalance has revealed a large adsorption-desorption process of the growing electropolyme...
Article
The aim of the present paper is to contribute to the elucidation of the molecular structures obtained on a platinum surface as this surface is submitted to an anodic potential (with respect to a silver reference electrode) when dipped into pure 2-methyl 2-propenenitrile (methacrylonitrile). Modified surfaces are examined using X- and UV-photoelectr...
Article
This paper presents a tentative extension of the Lewis acid-base concept to the case of an organic molecule interacting with a polarized metallic surface. Towards this aim, we make use of the Density Functional Theory (DFT) viewpoint on Lewis acid-base interactions. This theory has been shown to be relevant to describe adhesion processes at a molec...
Article
Application of an anodic potential under recycled argon atmosphere to a highly concentrated solution of N‐vinyl‐2‐pyrrolidone (5 mol.dm−3) allows to graft and polymerise the monomer onto a Pt or Au electrode. XPS, UPS and IRRAS spectroscopies reveal the presence of thin PVP films on these surfaces. XPS data point to the formation of C‐metal bonds...
Article
The set of the experimental techniques presented here is concerned with the in situ analysis like electrochemistry in organic media, electrochemical impedance spectroscopy (EIS) and ellipsometric spectroscopy whom combinated, enable the monitoring of the different steps of the growth of a polymer film by electropolymerization under cathodic polaris...
Article
The study of 4-vinylpyridine belongs to an experimental approach developed since the 80s in our laboratory, which consists in studying the ability of vinylic monomers to form under cathodic polarization (in a strictly controlled aprotic medium) high quality films, grafted and polymerized onto a metallic electrode. The electropolymerization of 4-vin...
Article
Methacrylonitrile was polymerized under cathodic polarization onto nickel electrodes. Compact polymer films strongly bound to the metal were obtained when using strictly controlled organic electrolytic solutions. The polymerization process was found to be highly dependent on the monomer concentration in the electrolytic solution. For a low monomer...
Conference Paper
A theoretical model of Lewis acid-base interactions, designed within the Density Functional Theory (DFT) formalism, is used to interpret some of the results obtained in the grafting of vinylic molecules (methacrylonitrile...) on metallic surfaces (Ni, pt) via electropolymerization. Global (electronic chemical potential, electronic softness) and loc...
Conference Paper
The interaction between polymerizable vinylic molecules (acrylonitrile, methacrylonitrile, N-vinylpyrrolidone) and metallic surfaces (Ni, Pt) is studied experimentally in order to establish the grounds of a molecular engineering of the polymer/metal bond. This work is a part of a more general study that gathers results obtained from quantum chemist...
Article
The electroinitiated polymerization of N-vinyl-2-pyrrolidone has been investigated. After electrolysis at controlled potential, a thin, covering, and homogeneous film of poly(N-vinyl-2-pyrrolidone) appears on the electrode. The insolubility of the polymer in its classical solvents implies the existence of a true chemical grafting of macromolecules...
Article
Full-text available
A low-energy contribution at 283.6 eV noted in the C1s region of the XPS spectrum of thin films of poly(methacrylonitrile) obtained via cathodic electropolymerization of 2-methyl-2-propenenitrile on nickel surfaces and recent electrochemical impedance measurements are strongly indicative of a chemical bond formed between the first monomer and metal...
Article
Under cathodic polarization in aprotic media some vinylic monomers like acrylonitrile and methacrylonitrile can be polymerized and strongly bound to a metallic surface (nickel for instance). The bonding of polymer films on metallic electrodes has been studied by electrochemical impedance spectroscopy combined with classical electrochemical methods...
Article
Mechanisms of formation and structure of the interface between an oxidized nickel surface and poly(2-methyl-2-propenenitrile) obtained by electropolymerization under cathodic polarization are studied by UPS and XPS spectroscopies. The results suggest that a direct interaction takes place between the monomer molecules and surface metallic sites free...
Article
Attempts to obtain polymer films by cathodic polarization of a nickel electrode in the presence of acrylonitrile, 2-butenenitrile, 3-butenenitrile, and 2-methyl-2-propenenitrile are reported. Surface characterizations are carried out through the combined use of UPS, XPS, and IRRAS. Acrylonitrile and 2-methyl-2-propenenitrile lead to adherent and ho...
Article
The formation of a polymer film obtained by cathodic polarization of a nickel electrode in the presence of 4-chlorostyrene has been studied for the first time. The different steps of the process were followed through the combined use of electrochemical analytical methods with surface-sensitive spectroscopy (AES and ESCA), ellipsometry, and IR and U...
Article
The use of specific experimental conditions leads to the development of a secondary electrode reaction corresponding to the development of the grafting and growth of the polymeric film onto the cathode surface. The use of both electrochemical in situ characterization (intensity-potential curves) and ex situ spectroscopic methods, such as UPS, XANES...
Article
Full-text available
Due to their interesting properties, carbon nanotubes (CNTs) have attracted particular attention for different application fields such as composite materials, microelectronics [1] and biology. Processing CNTs is a key point which often requires appropriate chemical modification of their surface in order to enhance their dispersability or to improve...

Projects