Dynamics of polymers in a particle-based mesoscopic solvent.

Area of Science:

• Polymer Physics
• Computational Chemistry
• Soft Matter Physics

Background:

• Understanding polymer dynamics in solution is crucial for materials science and biophysics.
• Accurate simulation of hydrodynamic interactions is essential for modeling polymer behavior.

Purpose of the Study:

• To investigate the dynamics of flexible polymer chains in solution using a hybrid simulation approach.
• To validate the accuracy of multiparticle-collision dynamics (MPCD) for capturing polymer hydrodynamics.
• To analyze scaling laws and long-time dynamics of polymer chains.

Main Methods:

• Combined multiparticle-collision dynamics (MPCD) and molecular-dynamics (MD) simulations.
• Inclusion of polymers with and without excluded-volume interactions.
• Systematic variation of MPCD solvent parameters to ensure proper hydrodynamic interactions.

Main Results:

• Hydrodynamic interactions were found to build up correctly with appropriate MPCD parameters.
• Center-of-mass diffusion coefficients exhibited length scaling consistent with theoretical predictions for short chains.
• The center-of-mass velocity autocorrelation function showed an algebraic long-time tail, decaying as (Dt)(-3/2).

Conclusions:

• The hybrid MPCD-MD method accurately captures polymer dynamics in solution.
• The study confirms theoretical scaling laws for diffusion and highlights the presence of long-time tails in polymer dynamics.
• Simulated intramolecular dynamics align well with the predictions of the Zimm model.