Modeling the dynamics of polymer solutions by dissipative particle dynamics.

摘要

In this volume, a relatively new simulation method---Dissipative Particle Dynamics (DPD) is used to simulate rheology and dynamics of dilute polymer solution and polymer melt.;The solvent quality effect on rheological properties of dilute polymer solution in shear flow is investigated by examining 10-bead FENE chain solutions of good solvent, near theta solvent and poor solvent. The simulations predict shear thinning in intrinsic viscosity and 1st normal stress for all solvent qualities, and a positive 2nd normal stress for the good solvent solution. The polymer chain in a good solvent solution exhibits more pronounced shear thinning in intrinsic viscosity and 1 st normal stress, and exhibits a smaller extent of chain expansion under shear flow than poor & near theta solvent solutions. The hydrodynamic interaction effect in DPD polymer solution is analyzed and benchmarked with theory, and shows good agreement with theoretical work.;The effects of Hookean and FENE spring types and internal viscosity effect is studied with the implicit hydrodynamic interactions and excluded volume effect in DPD dilute polymer solutions.;The DPD model is expanded to application on polymer melt through a segment anti-crossing mechanism designed to model entanglement dynamics. Simulations with new mechanism show the onset of entanglement dynamics, but investigation of fully entangled melts awaits further simulation work.