(404a) Self-Assembly of Aqueous Surfactants on Chemical and Morphological Heterogeneous Surfaces

The widespread interest in the self-assembly of surfactants on solid surfaces is motivated by many technological applications, including the manufacture of nano-structured materials using bottom-up strategies. Although much is known about the adsorption of surfactants on homogeneous flat surfaces from experiments, theory, and/or simulations, limited information is available, in quantifiable terms, regarding the adsorption of surfactants on surfaces with chemical and/or morphological heterogeneity. In this study the adsorption of model surfactants on patterned substrates has been investigated using equilibrium dissipative particle dynamics (DPD) simulations. Surfactant adsorption is allowed on troughs (considered at least in part hydrophobic) surrounded by a surface that effectively repels the surfactants. Our results suggest that the trough depth, the lateral size, and the distribution of hydrophobic sites on its surface lead to rich surfactant behaviour. Some of the structures observed in our simulations are not possible on flat homogeneous, nor on flat chemically heterogeneous surfaces. Once verified experimentally, our predictions could be useful, for example, for the design of new nano-structured materials and coatings.