The electrostatic persistence length calculated from Monte Carlo, variational and perturbation methods
(1997) In Journal of Chemical Physics 107(4). p.1279-1287- Abstract
Monte Carlo simulations and variational calculations using a Gaussian ansatz are applied to a model consisting of a flexible linear polyelectrolyte chain as well as to an intrinsically stiff chain with up to 1000 charged monomers. Addition of salt is treated implicitly through a screened Coulomb potential for the electrostatic interactions. For the flexible model the electrostatic persistence length shows roughly three regimes in its dependence on the Debye-Hückel screening length, κ-1. As long as the salt content is low and κ-1 is longer than the end-to-end distance, the electrostatic persistence length varies only slowly with κ-1. Decreasing the screening length, a controversial region is entered. We... (More)
Monte Carlo simulations and variational calculations using a Gaussian ansatz are applied to a model consisting of a flexible linear polyelectrolyte chain as well as to an intrinsically stiff chain with up to 1000 charged monomers. Addition of salt is treated implicitly through a screened Coulomb potential for the electrostatic interactions. For the flexible model the electrostatic persistence length shows roughly three regimes in its dependence on the Debye-Hückel screening length, κ-1. As long as the salt content is low and κ-1 is longer than the end-to-end distance, the electrostatic persistence length varies only slowly with κ-1. Decreasing the screening length, a controversial region is entered. We find that the electrostatic persistence length scales as √ξp/κ, in agreement with experiment on flexible polyelectrolytes, where ξp is a strength parameter measuring the electrostatic interactions within the polyelectrolyte. For screening lengths much shorter than the bond length, the κ-1 dependence becomes quadratic in the variational calculation. The simulations suffer from numerical problems in this regime, but seem to give a relationship half-way between linear and quadratic. A low temperature expansion only reproduces the first regime and a high temperature expansion, which treats the electrostatic interactions as a perturbation to a Gaussian chain, gives a quadratic dependence on the Debye length. For a sufficiently stiff chain, the persistence length varies quadratically with κ-1 in agreement with earlier theories.
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- author
- Ullner, Magnus LU ; Jönsson, Bo LU ; Peterson, Carsten LU ; Sommelius, Ola LU and Söderberg, Bo LU
- organization
- publishing date
- 1997-07-22
- type
- Contribution to journal
- publication status
- published
- in
- Journal of Chemical Physics
- volume
- 107
- issue
- 4
- pages
- 9 pages
- publisher
- American Institute of Physics (AIP)
- external identifiers
-
- scopus:0031185629
- ISSN
- 0021-9606
- language
- English
- LU publication?
- yes
- id
- d2e48467-dd19-4eab-9867-e864af682036
- date added to LUP
- 2016-10-03 19:13:40
- date last changed
- 2024-01-04 13:37:32
@article{d2e48467-dd19-4eab-9867-e864af682036,
abstract = {{<p>Monte Carlo simulations and variational calculations using a Gaussian ansatz are applied to a model consisting of a flexible linear polyelectrolyte chain as well as to an intrinsically stiff chain with up to 1000 charged monomers. Addition of salt is treated implicitly through a screened Coulomb potential for the electrostatic interactions. For the flexible model the electrostatic persistence length shows roughly three regimes in its dependence on the Debye-Hückel screening length, κ<sup>-1</sup>. As long as the salt content is low and κ<sup>-1</sup> is longer than the end-to-end distance, the electrostatic persistence length varies only slowly with κ<sup>-1</sup>. Decreasing the screening length, a controversial region is entered. We find that the electrostatic persistence length scales as √ξ<sub>p</sub>/κ, in agreement with experiment on flexible polyelectrolytes, where ξ<sub>p</sub> is a strength parameter measuring the electrostatic interactions within the polyelectrolyte. For screening lengths much shorter than the bond length, the κ<sup>-1</sup> dependence becomes quadratic in the variational calculation. The simulations suffer from numerical problems in this regime, but seem to give a relationship half-way between linear and quadratic. A low temperature expansion only reproduces the first regime and a high temperature expansion, which treats the electrostatic interactions as a perturbation to a Gaussian chain, gives a quadratic dependence on the Debye length. For a sufficiently stiff chain, the persistence length varies quadratically with κ<sup>-1</sup> in agreement with earlier theories.</p>}},
author = {{Ullner, Magnus and Jönsson, Bo and Peterson, Carsten and Sommelius, Ola and Söderberg, Bo}},
issn = {{0021-9606}},
language = {{eng}},
month = {{07}},
number = {{4}},
pages = {{1279--1287}},
publisher = {{American Institute of Physics (AIP)}},
series = {{Journal of Chemical Physics}},
title = {{The electrostatic persistence length calculated from Monte Carlo, variational and perturbation methods}},
volume = {{107}},
year = {{1997}},
}