engleski

Influence of structural and experimental parameters on self-assembly of nitrosobenzene derivatives on gold surface

Self-assembled monolayers (SAMs) are formed by the adsorption of organic molecules on metal surfaces and their spontaneous organization into highly ordered two-dimensional structures. The most studied systems are SAMs of organic molecules with sulphur, which are bound to the flat gold surface through Au-S bond. It has recently been found that molecules of aromatic C-nitroso compounds functionalized by a sulfur-containing group form ordered SAMs on the gold (111) surface. Owing to the property of aromatic C-nitroso monomers to dimerize to the corresponding azodioxides, it is also possible to form self-assembled bilayers (SABs) by interactions of nitroso groups exposed at the monolayer interface and free nitroso groups in solution through azodioxy bonds. In order to gain deeper insight into the formation mechanism and growth kinetics of nitroso/azodioxy adlayers, the influence of structural and experimental parameters (adsorption time and concentration of the solution) on the formation of SAMs and SABs of nitrosobenzene derivatives on the gold (111) surface was investigated. For this purpose, three nitrosobenzene derivatives with alkyl chains of different lengths in para-position relative to the nitroso group, ending with thiocyanate headgroups for adsorption on gold (111) surface, were synthesized. Molecular layers were prepared by immersing the gold (111) substrate in a solution of the corresponding nitrosobenzene derivative of known concentration for a defined time. The morphology, structural features and the thickness of the molecular layers of nitrosobenzene derivatives on the gold (111) surface were investigated by atomic force microscopy (AFM) and ellipsometry.

Self-assembled monolayers ; self-assembled bilayers ; aromatic C-nitroso compounds

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