Molecular dynamics simulations of ionic and nonionic surfactant micelles with a generalized born implicit‐solvent model

In recent years, all‐atom and coarse‐grained models have been developed andapplied to simulations of micelles and biological membranes. Here, we explorethe question of whether a combined all‐atom representation of surfactantmolecules and continuum description of solvent based on the generalized Bornmodel can be used to study surfactant micelles. Specifically, we report theparameterization of the GBSW model with a surface‐area dependent nonpolarsolvation energy term for dodecyl sulfate, dodecyl tetramethylammonium, anddodecyl triethyleneglycol ether molecules. In the parameterization procedure,the atomic Born radii were derived from the radial distribution functions ofsolvent charge and refined targeting the potential of mean force of dimerinteractions from explicit‐solvent simulations. The optimized radii were thenapplied in molecular dynamics simulations of the ionic and nonionic micelles.We found that the micelles are stable but more compact and rigid than inexplicit solvent as a consequence of the drastic reduction in solvation andmobility of surfactant monomers within the micelle. Based on these data and ourprevious work, we suggest that in addition to a more accurate description ofthe nonpolar solvation energy, the ruggedness in the short‐range interactionsdue to solvent granularity is a critical feature that needs to be taken intoaccount to accurately model processes such as micelle formation and proteinfolding in implicit solvent. Finally, the explicit‐solvent data presented hereoffers new insights into different conformational behavior of ionic andnonionic micelles which is valuable for understanding hydrophobic assembliesand of interest to the detergent industry. © 2011 Wiley Periodicals, Inc. J Comput Chem, 2011