Monocouches auto-assemblées d’organothiols mono- et bipodes sur le cuivre

Abstract

The present work is included in the framework of molecular assemblies on oxidizable metals surface and globally intends to create different functional coatings with specific properties. The general methodology involves the formation of Self-Assembled Monolayers (SAMs) of mono- or bipodal organothiols on copper substrates. The first part of this thesis highlights the feasibility of the grafting on polycrystalline and electroreduced copper substrate of alcanethiol molecules with a single (thiol, RSH) or a double anchoring group (dithiol R(SH)2 and dithiocarboxylic RS2H). It comes out that the nature of the anchoring group has a strong impact on the structural properties of the monolayer, but also on its electrochemical and chemical (after immersion in another organothiol solution) stabilities. The dithiol SAMs lead to a significant increase of electrochemical stability and surface coverage by comparison with thiol and dithiocarboxylic SAMs; meanwhile, the dithiocarboxylic monolayers lead to the less stable coatings. The second part of the study is devoted to the elaboration of amine terminated monolayers (NH2RSH or NH2R(SH)2) as promotor of adhesion between copper substrate and a polymer (epoxy resin or polyimide). In order to counter the reactivity of the amine function (oxidation and multilayers formation) and to obtain densely packed amine terminated SAMs, several optimisations of the processes are first investigated. A polymeric film (epoxy or polyimide) is then deposited on those monolayers: the presence of amine terminated SAMs on copper affords a significant increase of the copper-epoxy adhesion. However, this coating doesn’t show any improvement on the copper-polyimide adhesion. Finally, a bilayer film formed by an adsorbed first part (CF3O(CF2)2RSH or CF3O(CF2)2R(SH)2 SAM) and a second mobile part (perfluoropolyether lubricant) is achieved. The perfluoroether-alcanethiol and dithiol SAMs own high blocking and insulating properties, even if they are loosely packed. The spreading of a thin lubricant film on their surface then permits the formation of a homogeneous bilayer film with high wettability. Furthermore, the presence of a monolayer leads to a decrease of the lubricant mobility, and therefore an improvement of its retention on the copper surface. This lower mobility is more pronounced for monolayers with large interchain spacing.

Date of Award	12 Sept 2011
Original language	French
Awarding Institution	University of Namur
Supervisor	Zineb Mekhalif (Supervisor), Andre Peremans (Jury), Eric Perpete (President), Joseph DELHALLE (Jury), Christian AMATORE (Jury) & Arnaud Delcorte (Jury)