Modeling of aqueous poly(oxyethylene) solutions. 2. Mesoscale simulations

Area of Science:

• Computational Chemistry
• Polymer Physics
• Materials Science

Background:

• Atomistic simulations provide detailed insights into poly(oxyethylene) oligomer (POEn) solutions.
• Developing efficient mesoscale models is crucial for simulating larger systems and longer timescales.

Purpose of the Study:

• To construct and validate coarse-grained (CG) implicit-solvent potentials for POEn solutions.
• To assess the transferability and accuracy of these CG potentials across different concentrations and molecular sizes.
• To evaluate the computational speed-up and dynamic behavior captured by mesoscale simulations.

Main Methods:

• Iterative Boltzmann inversion technique used to develop CG potentials from atomistic simulations of POEn trimers and decamers.
• Comparison of structural properties (gyration radii, end-to-end distances, radial distribution functions) from CG and atomistic simulations against experimental data.
• Analysis of relaxation times and diffusion coefficients across different concentrations and chain lengths.

Main Results:

• State-specific CG potentials demonstrate transferability across a wide concentration range and to significantly larger molecules.
• Decamer-fitted potentials with dihedral interactions accurately reproduce experimental gyration radii up to 1500 monomers.
• Mesoscale simulations achieve a speed-up of approximately 3 orders of magnitude, with relaxation and diffusion being 1-2 orders of magnitude faster.

Conclusions:

• CG implicit-solvent models, particularly those derived from decamer simulations, are effective for studying POEn solutions.
• These mesoscale approaches significantly accelerate simulations while maintaining reasonable accuracy for structural and dynamic properties.
• The developed potentials enable efficient exploration of large-scale conformational changes and dynamics in polymer solutions.