Hydrodynamic- and viscosity-radius expansion factors of polymer chains with excluded volume: Monte Carlo methods

Abstract

In order to examine the effect of fluctuating (nonpreaveraged) hydrodynamic interaction on the hydrodynamic-radius expansion factor αH and also the viscosity-radius one αη, a Monte Carlo simulation study is made on the basis of the polymethylenelike rotational isomeric state chain in the Zimm rigid-body ensemble approximation. All the results obtained are consistent with the. recent finding (by Yamakawa's group) that the experimental values of αH are appreciably smaller than the values predicted by any available theory and rather agree with the theoretical and experimental values of αη, indicating that the effect is significant on αH but is negligibly small on αH if any. The present results along with the recent experimental ones also confirm the validity of the quasi-two-parameter scheme for αH and αη as well as for the gyration-radius expansion factor αS; i.e., these expansion factors are functions only of the scaled excluded-volume parameter z̃ defined in the Yamakawa-Stockmayer-Shimada theory of the excluded-volume effect in the Kratky-Porod wormlike chain and the helical wormlike chain. © 1996 American Institute of Physics.