Non-Equilibrium Coarse-Grained Molecular Dynamics Simulations of Polyelectrolytes under Shear

Molecular dynamics simulations were employed to explore the structures of polyelectrolytes under shear. A coarse-grained model with explicit solvent and counterions was combined with the dissipative particle dynamics thermostat to incorporate hydrodynamics in the non-equilibrium simulations. The spherical harmonic expansion technique is used to quantify the anisotropic structures under shear. We show that the deformation of the interchain structures is controlled by the cooperative diffusion mode associated with the correlation length, whereas the single-chain relaxation time is important for the distortion of the intrachain structures. Deep in the semi-dilute regime, only small structural distortions are observed for the total polymer scattering function, which is consistent with small-angle neutron scattering experiments. Our analysis also indicates that the microscopic deformation of polyelectrolytes is highly non-affine, in sharp contrast to the behavior of neutral polymers.