6533b854fe1ef96bd12ade75

RESEARCH PRODUCT

Grafted polymer layers under shear: A Monte Carlo simulation

subject

description

Endgrafted polymers at surfaces exposed to a shear flow are modeled by a nonequilibrium Monte Carlo method where the jump rate of effective monomers to neighboring lattice sites against the flow direction is smaller than in the flow direction, assuming that this difference in jump rates is proportional to the local velocity of the flowing fluid. In the dilute case of isolated chains, the velocity profile is assumed linearly increasing with the distance from the surface, while for the case of polymer brushes the screening of the velocity field is calculated using a parabolic density profile for the brush whose height is determined self‐consistently. Linear dimensions of isolated chains are obtained over a wide range of shear rates γ, and the deformation of the coil structure by the shear is studied in detail. For brushes it is found that the density profile and the distribution for the perpendicular coordinate zN of the free ends differ only little from the shear‐free case, while the distribution of the f...