Eur. Phys. J. Special Topics 225, 1683-1692 (2016)
https://doi.org/10.1140/epjst/e2016-60113-0

Regular Article

Simulations of stretching a flexible polyelectrolyte with varying charge separation

¹ Center for Integrated Nanotechnologies, Sandia National Laboratories, PO Box 5800, MS 1315, Albuquerque, NM 87185-1315, New Mexico, USA
² Materials Department and BMSE Program, University of California, Santa Barbara, California 93106, USA

Received: 15 April 2016
Revised: 16 June 2016
Published online: 22 July 2016

Abstract

We calculated the force-extension curves for a flexible polyelectrolyte chain with varying charge separations by performing Monte Carlo simulations of a 5000 bead chain using a screened Coulomb interaction. At all charge separations, the force-extension curves exhibit a Pincus-like scaling regime at intermediate forces and a logarithmic regime at large forces. As the charge separation increases, the Pincus regime shifts to a larger range of forces and the logarithmic regime starts are larger forces. We also found that force-extension curve for the corresponding neutral chain has a logarithmic regime. Decreasing the diameter of bead in the neutral chain simulations removed the logarithmic regime, and the force-extension curve tends to the freely jointed chain limit. This result shows that only excluded volume is required for the high force logarithmic regime to occur.