No abstract

Patterned surfaces presenting a high density of chemically reactive functional groups can be prepared through photolithography of self-assembled monolayers (SAM). In this paper, we report the synthesis and the evaluation of three reagents that can be used in SAM-photolithographic applications. These reagents are made up of a triethoxysilylpropylamine moiety in which the amine is temporarily blocked by photolabile protecting groups: NVOC (0-nitroveratryloxycarbonyl), ONB (0-nitrobenzyl), or DDZ (a,a-dimethyl-3,s-dimethoxybenzyloxycarbonyl). The presence of the triethoxysilyl group allows selfassembled monolayer formation. Release of chemically reactive amino groups is achieved by irradiation of the surface. An electroanalytical method was developed and used to monitor and optimize the three steps of the methodology occurring on surfaces: monolayer formation, photodeprotection, and subsequent functionalization of the released amino groups. Quantitative information on the efficiency of the photodeprotection step was obtained by this method. It was found that the DDZ group is superior to the ONB and NVOC photolabile protecting groups for SAM-photolithographic applications. Percentages of liberated amino groups are generally above 50% with the DDZ group, while they are generally inferior to 25% and 2% for NVOC and ONB, respectively. These differences are attributed to the destruction of some of the released amino groups through a subsequent reaction with the photoproduct, o-nitrosobenzaldehyde for ONB and 3,4-dimethoxy-6-nitrosobenzaldehyde for NVOC, and to partial loss or destruction of the monolayer during prolonged irradiations.Key words: self-assembled monolayers, surface modification, photolithography, photolabile protecting groups, cyclic voltammetry.R6umC : Des motifs prCsentant une haute densite de groupes fonctionnels chimiquement rCactifs peuvent Stre prCparCs sur des surfaces i l'aide de la photolithographie de monocouches auto-assemblCes (MAA). Dans cet article, nous relatons la synthkse et 1'Cvaluation de trois rCactifs pouvant Ctre utilisCs dans des applications de la photolithographie-MAA. Ces rCactifs sont constituCs d'un fragment triCthoxysilylpropylamine dont la fonction amine est temporairement bloquCe par des groupement protecteurs photolabiles : NVOC (0-nitrovCratryloxycarbonyle), ONB (0-nitrobenzyle) ou DDZ (a,a-dimCthy1-3,sdimCthoxybenzyloxycarbonyle). La prCsence du groupe triCthoxysilyle permet la formation de monocouches auto-assemblCes. La libCration des groupements amines chimiquement rCactifs est accomplie par irradiation de la surface. Une mCthode Clectroanalytique a Ct C dCveloppCe et utilisCe pour suivre et optimiser les trois Ctapes de la mCthodologie se produisant i la surface : la formation de la monocouche, la photodCprotection et la fonctionnalisation subskquente des groupes amines libCrCs. De l'information quantitative sur I'efficacitC de 1'Ctape de dkprotection a Ct C obtenue par cette mCthode. I1 a Ct C dCcouvert que le groupe DDZ est supCrieur aux groupes protecteurs...

The inhibition performance of sodium gluconate (SG), cetyltrimethylammonium bromide (CTAB) and their mixture (SG/ CTAB) on the corrosion behavior of α-brass in 0.5 M H 2 SO 4 solution has been investigated by potentiodynamic polarization, electrochemical impedance spectroscopy (EIS), Scanning Electron Microscope with Energy-Dispersive Spectrometer (SEM-EDS), Inductively Coupled Plasma Spectrometry (ICPS) and molecular dynamics (MD) simulation techniques. The results reveal that SG with 5ppm CTAB, noted SG/CTAB, acts as a good corrosion inhibitor and its inhibition efficiency reached 89% after 24 h immersion in sulfuric acid solution, but slightly decreased at higher temperatures. The polarization curves displayed that SG/CTAB acts as a cathodic-kind inhibitor. Electrochemical impedance spectroscopy (EIS) studies revealed that the addition of 5ppm CTAB to different concentrations of SG considerably increases the corrosion resistance of α-brass. The SEM-EDS and ICPS analyses support the experimental results. Further, molecular dynamics (MD) simulations were used to understand the adsorption profiles of SG/CTAB on Cu(111) and Zn(111) surfaces.