Molecular dynamics simulations of ionic and nonionic surfactant micelles with a generalized Born implicit-solvent...

Area of Science:

• Computational Chemistry
• Physical Chemistry
• Soft Matter Physics

Background:

• All-atom and coarse-grained models are used for simulating micelles and membranes.
• Implicit solvent models offer computational efficiency for large systems.

Purpose of the Study:

• To evaluate the suitability of a combined all-atom and continuum solvent model for studying surfactant micelles.
• To parameterize the generalized Born Surface generalized Born, Water (GBSW) model for specific surfactant molecules.

Main Methods:

• Parameterization of the GBSW model using surface-area dependent nonpolar solvation energy.
• Derivation of atomic Born radii from radial distribution functions and refinement against dimer interactions.
• Molecular dynamics simulations of ionic and nonionic micelles using the optimized model.

Main Results:

• The GBSW model successfully simulated stable surfactant micelles.
• Micelles simulated in implicit solvent were more compact and rigid compared to explicit solvent simulations.
• Reduced solvation and mobility of surfactant monomers within the micelle were observed.

Conclusions:

• The GBSW model provides a stable, albeit more compact, representation of surfactant micelles.
• Accurate modeling of micelle formation and protein folding requires accounting for solvent granularity and nonpolar solvation energy.
• Explicit solvent simulations offer insights into conformational differences between ionic and nonionic micelles.