Quantitative bridging between full-atomistic and bead-spring models for polybutadiene and poly(butadiene-styrene)...

Area of Science:

• Polymer Physics
• Computational Chemistry
• Materials Science

Background:

• Bridging full-atomistic and coarse-grained polymer models is computationally challenging.
• Existing methods often require long chain simulations for parameter determination.

Purpose of the Study:

• To develop a practical and quantitative method for bridging polymer models using short chain simulations.
• To incorporate molecular weight dependence into polymer model bridging.

Main Methods:

• Performed full-atomistic simulations of polybutadiene and poly(butadiene-styrene) with 20-40 repeating units.
• Constructed coarse-grained models using bead-spring chains with bending rigidity.
• Derived spatial conversion factors from conformational statistics, including molecular weight dependence.

Main Results:

• Developed empirical functions to account for molecular weight dependence in conformational statistics.
• Achieved rigorous bridging, ensuring coarse-grained structural distributions match full-atomistic ones.
• Successfully predicted segmental diffusion in long polymer chains (200 repeating units) using the developed method.

Conclusions:

• The proposed method provides a practical and accurate way to bridge polymer models.
• Incorporating molecular weight dependence is crucial for rigorous bridging.
• This approach reduces computational cost while maintaining high accuracy in polymer simulations.