Physics – Condensed Matter – Soft Condensed Matter
Scientific paper
2000-02-29
Physics
Condensed Matter
Soft Condensed Matter
Revised version. Long chain limit analysis has been deleted. An improved and corrected examination of the long chain limit wil
Scientific paper
10.1021/ma0006880
Linear viscoelastic properties for a dilute polymer solution are predicted by modeling the solution as a suspension of non-interacting bead-spring chains. The present model, unlike the Rouse model, can describe the solution's rheological behavior even when the solvent quality is good, since excluded volume effects are explicitly taken into account through a narrow Gaussian repulsive potential between pairs of beads in a bead-spring chain. The use of the narrow Gaussian potential, which tends to the more commonly used delta-function repulsive potential in the limit of a width parameter "d" going to zero, enables the performance of Brownian dynamics simulations. The simulations results, which describe the exact behavior of the model, indicate that for chains of arbitrary but finite length, a delta-function potential leads to equilibrium and zero shear rate properties which are identical to the predictions of the Rouse model. On the other hand, a non-zero value of "d" gives rise to a prediction of swelling at equilibrium, and an increase in zero shear rate properties relative to their Rouse model values. The use of a delta-function potential appears to be justified in the limit of infinite chain length. The exact simulation results are compared with those obtained with an approximate solution which is based on the assumption that the non-equilibrium configurational distribution function is Gaussian. The Gaussian approximation is shown to be exact to first order in the strength of excluded volume interaction, and is found to be accurate above a threshold value of "d", for given values of chain length and strength of excluded volume interaction.
No associations
LandOfFree
Rouse Chains with Excluded Volume Interactions: Linear Viscoelasticity does not yet have a rating. At this time, there are no reviews or comments for this scientific paper.
If you have personal experience with Rouse Chains with Excluded Volume Interactions: Linear Viscoelasticity, we encourage you to share that experience with our LandOfFree.com community. Your opinion is very important and Rouse Chains with Excluded Volume Interactions: Linear Viscoelasticity will most certainly appreciate the feedback.
Profile ID: LFWR-SCP-O-565514