Europhys. Lett.
Volume 75, Number 1, July 2006
Page(s) 77 - 83
Section Condensed matter: structural, mechanical and thermal properties
Published online 02 June 2006
Europhys. Lett., 75 (1), pp. 77-83 (2006)
DOI: 10.1209/epl/i2006-10067-y

Dynamic scaling in dilute polymer solutions: The importance of dynamic correlations

P. Sunthar and J. Ravi Prakash

Department of Chemical Engineering, Monash University Melbourne, VIC 3800, Australia

received 16 January 2006; accepted in final form 3 May 2006
published online 2 June 2006

The swelling $\ensuremath{\alpha_{\mathrm{H}}} $ of the hydrodynamic radius of a polymer, obtained using Brownian dynamics simulations of the continuum Edwards model, is found to obey a crossover in the excluded-volume parameter z, which is significantly different from that observed for the swelling $\ensuremath{\alpha_{\mathrm{g}}} $ of the radius of gyration. It is shown that this difference arises due to contributions from dynamic correlations to the diffusivity, which are ignored in the commonly used definition of hydrodynamic radius based on the Kirkwood expression. Simulated values of $\ensuremath{\alpha_{\mathrm{H}}} $ are found to be in remarkable agreement with experimental measurements

61.25.Hq - Macromolecular and polymer solutions; swelling.
82.35.Lr - Physical properties of polymers.
83.10.Mj - Molecular dynamics, Brownian dynamics.

© EDP Sciences 2006