Multiscale Molecular Dynamics Simulations of Model Hydrophobically Modified Ethylene Oxide Urethane Micelles.
The flower-like micelles of various aggregation numbers of a model hydrophobically modified ethylene oxide urethane (HEUR) molecule, C16E45C16, and their corresponding starlike micelles, containing the surfactants C16E22 and C16E23, were studied by atomistic and coarse-grained molecular dynamic (MD) simulations. We used free energies from umbrella sampling to calculate the size distribution of micelle sizes and the average time for escape of a hydrophobic group from the micelle. Using the coarse-grained MARTINI force field, the most probable size of the model HEUR molecule was thereby determined to be about 80 hydrophobes per micelle and the average hydrophobe escape time to be about 0.1 s, both of which are consistent with previous experimental studies. Atomistic simulations reveal that hydrogen bond formation and the mean lifetime of hydration waters of the poly(ethylene oxide) (or PEO) groups are location-dependent in the HEUR micelle, with PEO groups immediately adjacent to the C16 groups forming the fewest hydrogen bonds with water and having hydration waters with longer lifetimes than those of the PEO groups located further away from the C16 groups.
Department of Chemical Engineering and ‡Departments of Mechanical Engineering, Biomedical Engineering, and Macromolecular Science and Engineering Program, University of Michigan , Ann Arbor, Michigan 48109, United States.
Fang
F
Yuan
Department of Chemical Engineering and ‡Departments of Mechanical Engineering, Biomedical Engineering, and Macromolecular Science and Engineering Program, University of Michigan , Ann Arbor, Michigan 48109, United States.
Ronald G
RG
Larson
D006860:Hydrogen Bonding; D057927:Hydrophobic and Hydrophilic Interactions; D008823:Micelles; D056004:Molecular Dynamics Simulation; D011092:Polyethylene Glycols / Q000737:chemistry; D013816:Thermodynamics; D014520:Urethane / Q000031:analogs & derivatives / Q000737:chemistry*; D014867:Water / Q000737:chemistry
D008823:Micelles; D014867:Water; D014520:Urethane; D011092:Polyethylene Glycols