Deformation and orientation of flexible polymers in solution under shear flow: A new picture for intermediate reduced shear rates

An N-bead chain (9 ≤ N ≤ 50) in solvent subjected to steady shear flow with shear rate γ is treated by molecular dynamics simulation in order to analyze in a systematic way the deformation and the alignment of polymers in such a nonequilibrium stationary state. The reduced shear rate β = yτN, where τN is the chain longest relaxation time, is the key quantity used to connect real experiments and simulations. Our results for good solvent conditions suggest that chains of various lengths do obey anisotropic scaling laws; β-dependent Flory exponents for each principal axis of the gyration tensor are extracted from the global dimensions of the deformed chains and from their internal spatial correlations. The good agreement between the molecular dynamics data with results of experiments on dilute solutions of polymers subject to Couette flow supports the proposed scaling picture. © 1995, American Chemical Society. All rights reserved.