The self-assembly of surfactants from a bulk phase onto solid surfaces is of interest in a range of technical and biological processes. New variables associated with the solid surface lead to a phase behavior which is considerably richer than for bulk solutions. Experimentally observed structures include spheres, bilayers, hemi-cylinders and hemi-spheres. Despite the widespread interest in such structures, the underlying principles governing their formation and properties have resisted attempts at theoretical and computational treatments because of the large length and time scales involved. Conventional atomistic computational treatments cannot encompass such a range. However, atomistic interactions such as hydrogen bonding have been shown to be essential to obtain the correct phase behavior. The required length and time scales can be reached using meso-scale methods such as dissipative particle dynamics (DPD), but the atomistic detail is lost. To resolve this dilemma, we employ a multi-scale simulation scheme that allows us to map the fully atomistic system of nonionic poly(oxyethylene) alkyl ether surfactant molecules onto the meso-scale in the bulk and on surfaces. We develop meso-scale effective potentials using directly atomistic trajectories using methods based upon the force-matching approach [1,2]. Comparisons with experiment will be made.

[1] F. Ercolessi and J.B. Adams, "Interatomic Potentials from 1st-Principles Calculations - the Force-Matching Method," Europhys. Lett., 26 583 (1994). [2] S. Izvekov, S. and G.A. Voth, "Multiscale Coarse Graining of Liquid-State Systems," J. Chem. Phys., 123 134105 (2005).