The effect of a solid wall on polymer chain behavior under shear flow

Abstract

Molecular dynamics computer simulations are used to investigate the properties of isolated bead–rod chains with excluded volume effects under a simple shear flow. With the help of the collisional dynamics technique, the simulations are performed with both the chains end grafted to an impenetrable wall and the isolated free-space chains immersed in a solvent. The comparison of these chains shows up the effect of the wall presence. We have calculated both the microscopic properties (such as end-to-end distance of polymer chain, the deformation ratio) and the macroscopic rheological properties of the model polymer solution (such as shear viscosity, first normal stress difference). A comparative analysis of the chains dynamics shows that the response of the grafted chains to simple shear flow is much different from that of the free chains. It was demonstrated that the grafting of polymer chains also gives rise to the distinctive rheological properties of the polymer solutions. For example, the effective viscosity of the grafted chains is an order of magnitude higher then the viscosity of the free chains.