We present and discuss results obtained by an extensive nonequilibrium molecular dynamics computer simulation study of polymer solutions under shear, where the chain consists of N beads connected by a finitely extendable nonlinear elastic (FENE) spring force and the solvent is explicitly taken into account. Various scaling laws are extracted from the data which allow one to predict the qualitatives and to certain extent also quantitativesstructural and rheological behavior of polymer solutions under good solvent conditions. For most quantities, the results drawn from simulation are compared with experimental data and theoretical predictions which are based on similar models (e.g., harmonic bond potentials or Brownian dynamics methods). Specifically, and in contrast to common theoretical approaches, the simulation yield information about a set of different but characteristic relaxation times, which determine the rheological and structural behavior (for example, flow birefringence, structure factor, rotational dynamics) separately, the difference either resulting from the underlying static or dynamic nature or from relaxation processes which act on different length scales.

In this article, we establish the validity of a relation between the true angular velocity and gyration tensor for a dilute polymer solution in the case of a steady shear flow by means of nonequilibrium molecular dynamics computer simulation. The microscopic model for a polymer molecule immersed in a solution composed of monomers incorporates the effects of hydrodynamic interaction through the presence of explicit solvent monomers and the effect of finite stretchability of chains. In the strong flow regime, we observe regular and irregular dynamical behavior which is inherently connected with the nonlinearities in the equations of motion which come along with finite extendability of polymer chains. The microscopic dynamics underlying the simple relationship, and in particular the time series, the correlated rotation and deformation behavior, and cross-correlations between several structural quantities are investigated in detail. The results allow for a test of more efficient implementations, which aim to describe polymer dynamics considering hydrodynamic interactions by using ad hoc Langevin equations for the conformational variables.

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