Monte Carlo Simulation of Polyelectrolyte Gels:  Effects of Polydispersity and Topological Defects

Edgecombe, Samuel; Linse, Per

doi:10.1021/ma0700633

Cited by 37 publications

(44 citation statements)

References 36 publications

(82 reference statements)

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“…[13][14][15][16][17] Corresponding simulations have also been done, [18][19][20][21][22][23] confirming the basic picture that the entropy of the counterions exerts an extra osmotic pressure which in turn increases the swelling capacity of the hydrogels. Thus determining the location of these counterions within the network, and specifically the investigation of ion condensation around the polymer chains, is an important aspect of hydrogel research.…”

Section: Introductionmentioning

confidence: 55%

Comparison of a hydrogel model to the Poisson–Boltzmann cell model

Claudio

Kremer

Holm

2009

The Journal of Chemical Physics

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We have investigated a single charged microgel in aqueous solution with a combined simulational model and Poisson-Boltzmann theory. In the simulations we use a coarse-grained charged bead-spring model in a dielectric continuum, with explicit counterions and full electrostatic interactions under periodic and nonperiodic boundary conditions. The Poisson-Boltzmann hydrogel model is that of a single charged colloid confined to a spherical cell where the counterions are allowed to enter the uniformly charged sphere. In order to investigate the origin of the differences these two models may give, we performed a variety of simulations of different hydrogel models which were designed to test for the influence of charge correlations, excluded volume interactions, arrangement of charges along the polymer chains, and thermal fluctuations in the chains of the gel. These intermediate models systematically allow us to connect the Poisson-Boltzmann cell model to the bead-spring model hydrogel model in a stepwise manner thereby testing various approximations. Overall, the simulational results of all these hydrogel models are in good agreement, especially for the number of confined counterions within the gel. Our results support the applicability of the Poisson-Boltzmann cell model to study ionic properties of hydrogels under dilute conditions.

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Section: Introductionmentioning

confidence: 55%

Comparison of a hydrogel model to the Poisson–Boltzmann cell model

Claudio

Kremer

Holm

2009

The Journal of Chemical Physics

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“…Additionally, it is not clear how different chain length heterogeneities like e.g. a Flory-Schulz distribution would impact the results reported by [35]. Representing a broad chain length distribution requires to simulate many chains in a unit cell, hence a huge computational effort.…”

Section: Chain Length Polydispersitymentioning

confidence: 99%

Cell Model Approaches for Predicting the Swelling and Mechanical Properties of Polyelectrolyte Gels

Landsgesell

Holm

2019

Macromolecules

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We present two successive mean-field approximations for describing the mechanical properties and the swelling equilibrium of polyelectrolyte gels in contact with a salt solution. The first mean-field approximation reduces the many-chain problem of a gel to a corresponding single chain problem. The second mean-field step integrates out the degrees of freedom of the flexible chain and the ions. It replaces the particle-based description of the polyelectrolyte with suitable charge distributions and an effective elasticity term. These simplifications result in a computationally very efficient Poisson-Boltzmann cell-gel description. Despite their simplicity, the single chain cell-gel model shows excellent and the PB model very good agreement with explicit molecular dynamics simulations of the reference periodic monodisperse network model for varying chain length, polymer charge fraction, and external reservoir salt concentrations. Comparisons of our models to the Katchalsky model reveal that our approach is superior for strongly charged chains and can also predict the bulk moduli more accurately. We further discuss chain length polydispersity effects, investigate changes in the solvent permittivity, and demonstrate the robustness of our approach to parameter variations coming from several modeling assumptions.

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“…Edgecombe and Linse [102] addressed the influence of polydispersity and topological defects on the swelling behavior of neutral and PE gels under salt-free conditions. To introduce polydispersity, they modified the default model such that two chains were made shorter and two longer than the remaining ones.…”

Section: Salt-free Athermal Gelsmentioning

confidence: 99%