Adsorption of vinyl trimethoxysilane and formation of vinyl siloxane nanolayers on zinc surface from aqueous solution

• Published in: Protection of metals and physical chemistry of surfaces Vol. 52; no. 6; pp. 964 - 971
• Main Authors: Petrunin, M. A., Maksaeva, L. B., Yurasova, T. A., Gladkikh, N. A., Terekhova, E. V., Kotenev, V. A., Kablov, E. N., Tsivadze, A. Yu
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01-11-2016; Springer Nature B.V
• Subjects: Adsorption; Aqueous solutions; Characterization and Evaluation of Materials; Chemical bonds; Chemistry and Materials Science; Corrosion; Corrosion and Coatings; Hydrogen bonds; Industrial Chemistry/Chemical Engineering; Inorganic Chemistry; Isotherms; Materials Science; Mathematical models; Metal surfaces; Metallic Materials; Microbalances; Nonferrous metals; Oligomers; Physical chemistry; Physicochemical Processes at the Interfaces; Quartz crystals; Siloxanes; Surface chemistry; Thermodynamics; Thickness; Tribology; Zinc
• ISSN: 2070-2051; 2070-206X
• DOI: 10.1134/S2070205116060150

The method of quartz crystal microbalance is used to study adsorption of vinyl trimethoxysilane (VS) on the surface of zinc from an aqueous solution. Adsorption isotherms are obtained. Approaches corresponding to the known adsorption isotherms are used for interpretation of adsorption data: Langmuir, BET, Flory–Huggins, Langmuir multicenter, Temkin, and Langmuir–Freundlich. It is shown that silanes are adsorbed on the surface of thermally deposited zinc from aqueous solutions and displace adsorbed water from the surface by occupying more than six adsorption sites on the surface. It is found that monolayer coverage of the zinc surface is reached at a concentration of the VS solution of 1 × 10
–4
M. The neighboring adsorbate molecules can interact, forming siloxane dimers and trimers bound to the metal surface by either covalent or hydrogen bonds. Adsorption heats are calculated using different adsorption models. It is shown that VS is chemosorbed on the surface of zinc. An increase in the concentration of the VS solution up to 0.1 M results in formation of polycondensed siloxane oligomers on the surface with polycondensation degree
n
= 8–12. Oligomer surface fragments are connected with each other by hydrogen bonds and are connected with the surface by Zn–O–Si bridge bonds. The overall thickness of such a layer is 10–12 nm or ten molecular layers.