Collapse and expansion kinetics of a single polyelectrolyte chain with hydrodynamic interactions

Fuente: arXiv
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Auteurs principaux: Yuan, Jiaxing, Curk, Tine
Format: Preprint
Publié: 2024
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author Yuan, Jiaxing
Curk, Tine
author_facet Yuan, Jiaxing
Curk, Tine
contents We investigate the collapse and expansion dynamics of a linear polyelectrolyte (PE) with hydrodynamic interactions. Using dissipative particle dynamics with a bead-spring PE model, long-range electrostatics and explicit ions we examine how the timescales of collapse $t_\text{col}$ and expansion $t_\text{exp}$ depend on the chain length $N$, and obtain scaling relationships $t_\text{col}\sim N^α$ and $t_\text{exp}\sim N^β$. For neutral polymers, we derive values of $α=0.94\pm0.01$ and $β=1.97\pm0.10$. Interestingly, the introduction of electrostatic interaction markedly shifts $α$ to $α\approx1.4\pm0.1$ for salt concentrations within $c=10^{-4}$ M to $10^{-2}$ M. A reduction in ion-to-monomer size ratio noticeably reduces $α$. On the other hand, the expansion scaling remains approximately constant, $β\approx 2$, regardless of salt concentration or ion size considered. We find $β> α$ for all conditions considered, implying that expansion is always slower than collapse in the limit of long polymers. This asymmetry is explained by distinct kinetic pathways of collapse and expansion processes.
format Preprint
id arxiv_https___arxiv_org_abs_2402_00146
institution arXiv
publishDate 2024
record_format arxiv
spellingShingle Collapse and expansion kinetics of a single polyelectrolyte chain with hydrodynamic interactions
Yuan, Jiaxing
Curk, Tine
Soft Condensed Matter
Statistical Mechanics
We investigate the collapse and expansion dynamics of a linear polyelectrolyte (PE) with hydrodynamic interactions. Using dissipative particle dynamics with a bead-spring PE model, long-range electrostatics and explicit ions we examine how the timescales of collapse $t_\text{col}$ and expansion $t_\text{exp}$ depend on the chain length $N$, and obtain scaling relationships $t_\text{col}\sim N^α$ and $t_\text{exp}\sim N^β$. For neutral polymers, we derive values of $α=0.94\pm0.01$ and $β=1.97\pm0.10$. Interestingly, the introduction of electrostatic interaction markedly shifts $α$ to $α\approx1.4\pm0.1$ for salt concentrations within $c=10^{-4}$ M to $10^{-2}$ M. A reduction in ion-to-monomer size ratio noticeably reduces $α$. On the other hand, the expansion scaling remains approximately constant, $β\approx 2$, regardless of salt concentration or ion size considered. We find $β> α$ for all conditions considered, implying that expansion is always slower than collapse in the limit of long polymers. This asymmetry is explained by distinct kinetic pathways of collapse and expansion processes.
title Collapse and expansion kinetics of a single polyelectrolyte chain with hydrodynamic interactions
topic Soft Condensed Matter
Statistical Mechanics
url https://arxiv.org/abs/2402.00146