Molecular Dynamics Simulations of Cetyltrimethylammonium Bromide (CTAB) Micelles and their Interactions with a Gold Surface in Aqueous Solution

• Published in: Journal of the Brazilian Chemical Society 2018-01, Vol.29 (1), p.191-199
• Main Authors: da Silva, José, Dias, Roberta, da Hora, Gabriel, Soares, Thereza, Meneghetti, Mario
• Format: Article
• Language: English
• Subjects: CHEMISTRY, MULTIDISCIPLINARY
• ISSN: 0103-5053; 1678-4790
• DOI: 10.21577/0103-5053.20170130

Surfactants are molecular structures with remarkable physicochemical properties and applications. Most of their characteristics are due to their ability to promote aggregation and interactions with different interfaces. The scarcity of theoretical studies dedicated to evaluating the forces involved in these interactions prompted us to propose other models capable of reproducing the experimental data in better ways. We carried out molecular dynamics (MD) simulations to obtain a model for cetyltrimethylammonium bromide (CTAB), selected from gromos54a7 force field parameters, that better describes most of its behaviors in aqueous solution (micellar structure, counterion dissociation, etc.) and its adsorption pattern on a gold surface. The parameters adopted for one of the models were able to mimic several characteristics suggested by experimental measurements of the CTAB micelles, as well their adsorption pattern on a gold surface. Indeed, this model was able to obtain quasi-spherical micelles, as well as a pattern of adjacent cylindrical micelles with alkyl chain interactions on a gold surface.