This thesis is included in the framework of elaboration of organic nanolayers on surfaces of oxydizable metals by the formation of self-assembled monolayers (SAMs) of organothiols, organoselenols and organophosphonic acids. The metal of interest for this work is copper in view of the great challenges in terms of surface chemistry and fundamental questions concerning the interface between the metal and the molecules considered. To achieve our objectives, this substrate has been studied in three possible states of surface depending on the type of monolayers investigated, namely: naturally oxidized, reduced (without oxide) and strongly oxidized. The first part of this thesis has demonstrated the effective grafting of alkanethiols and alkaneselenols on a reduced copper substrate. The best quality of SAMs of thiol (-SH)/selenol (-SeH) in comparison with their dehydrogenated counterparts disulfide (-S-S-)/diselenide (-Se-Se-) has been proved, with a benefit for the selenol. Based on preliminary results, an optimization study of the self-assembly of SAMs of thiol (-SH)/selenol (-SeH) was considered. Initially, optimization of immersion time for the elaboration of these layers has highlighted the achievement of well-organized systems with an advantage for the SAMs of selenols. In a second step, the stability of these layers towards an ageing in the air and immersion in an antagonist solution was investigated. The first study showed the best stability for selenol for a long time of elaboration. In the second study, a process of intercalation of antagonist molecules within the defects of the initial layer has been demonstrated for both direction of immersion considered. The second part of this thesis has studied the influence of the presence of an oxide layer on the feasibility, quality and stability of SAMs of thiols and selenols compared to the situation on a reduced copper. The stability in ageing showed better stability for selenols as for a reduced copper. On the other hand, the stability by immersion showed a process of exchange and displacement of molecules, indicating that the SAMs on oxidized copper are less stable than on reduced copper. From these studies, it appears that selenols show very good properties (reduction of the oxide layer, blocking, organization, …) either on an oxidized or reduced copper substrate. However, a preliminary reduction of the substrate is essential to obtain the most reproducible layers possible with a robust and stable interface. Finally, a new approach was introduced on the copper, taking advantage of its oxide naturally present. Grafting of organophosphonic acids was successfully completed.
Greffage de nanofilms organiques sur le cuivre
Fonder, G. (Author). 29 Oct 2010
Student thesis: Doc types › Doctor of Sciences