A ‘Partially Clothed’ Pivot Algorithm for Model Polyelectrolyte Solutions

Gordon, Heather L.; Valleau, J. P.

doi:10.1080/08927029508022030

Cited by 24 publications

(30 citation statements)

References 60 publications

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“…[57][58][59] After each conformation modification, ΔE tot = E final tot − E initial tot is accepted or rejected according to the Metropolis algorithm. The PA conformations are modified by well-known specific movements such as kink-jump, end-bond, reptation, partially clothed pivot and chain translation.…”

Section: Modelmentioning

confidence: 99%

Modelling the interaction processes between nanoparticles and biomacromolecules of variable hydrophobicity: Monte Carlo simulations

Carnal

Clavier

Stoll

2015

Environ. Sci.: Nano

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The conformational properties and formation of a complex between a weak flexible biomacromolecule chain of variable hydrophobicity and one negatively charged nanoparticle in the presence of explicit counterions are investigated here using Monte Carlo simulations. The influence of the charge distribution and hydrophobicity, monomer distribution of the chain as well as the pH of the solution are systematically investigated. It is shown that the isolated chain conformations, built with random and block distribution of carboxylic, amino and hydrophobic groups, are the result of the subtle competition between intrachain attractive and repulsive electrostatic interactions as well as intrachain attractive short-range interactions due to hydrophobic properties. Extended conformations are found at low and high pH and folded conformations at physiological pH when hydrophilic and block polymer chains are considered. On the other hand, hydrophobic chain conformations do not show pH dependency and remain folded. The intrachain attractive electrostatic interactions clearly promote the deprotonation of carboxylic groups at low pH and the protonation of amino groups at high pH with higher efficiency for hydrophilic chains. The additional set of electrostatic interactions due to the presence of one negatively charged nanoparticle limits the deprotonation of carboxylic groups at low pH. Moreover, the attractive interactions between the biomacromolecule and the nanoparticle allow to observe the formation of a complex considering intermediate and hydrophilic chains even close to the chain isoelectric point due to the charge inhomogeneity distribution. Hydrophobic chain segments are not affected by the presence of the nanoparticle and remain desorbed. In all cases, the presence of one nanoparticle influences the biomacromolecule structures and acid/base properties, leading to more stretched conformations

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Section: Modelmentioning

confidence: 99%

Modelling the interaction processes between nanoparticles and biomacromolecules of variable hydrophobicity: Monte Carlo simulations

Carnal

Clavier

Stoll

2015

Environ. Sci.: Nano

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“…54 The polyelectrolyte position is modified by specific movements (kink-jump, endbond, reptation, and partially clothed pivot [55][56][57] ). All counterions and salt particles are moved through the box by translation movements.…”

Section: Model and Monte Carlo Simulationsmentioning

confidence: 99%

Influence of Explicit Ions on Titration Curves and Conformations of Flexible Polyelectrolytes: A Monte Carlo Study

2010

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Acid/base and conformational properties of a weak polyelectrolyte chain surrounded by explicit ions (counterions and salt particles) are investigated using Monte Carlo simulations. The influence of the pH, monomer size, presence of explicit ions, salt particles, salt size, and valency on the polyelectrolyte titration process is systematically investigated. It is shown that the presence of explicit ions, the increase in pH and monomer sizes, and the decrease in salt radius are parameters that favor the monomer deprotonation processes hence affecting the global acid/base polyelectrolyte chain properties. The competition between attractive and repulsive, long-range and local electrostatic interactions leads to a heterogeneous distribution of charges and ions along the polyelectrolyte backbones. This subtle electrostatic competition leads to equilibrated chain conformations ranging from extended to globular conformations. A simple screening effect is achieved with monovalent salt resulting in a slight limitation of the formation of extended structures at high pH values. Focusing on trivalent salt, the local complexation of several chain monomers around each trivalent cation leads to the formation of collapsed structures. The decrease in the size of trivalent cations promotes the deprotonation process, in particular, when trivalent salt cations are smaller than the monomer size.

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“…To circumvent this problem, we have used the "partially clothed" pivot algorithm proposed by Gordon and Valleau [18]. Having chosen a pivot P and the corresponding end part of the polymer, we look for all counterions at a distance less than d of this polymer part (the distance from the polymer is defined as the distance to the closest monomer).…”

Section: Monte Carlo Movesmentioning

confidence: 99%

“…Each of these counterions is rotated in block with the part of the polymer, with a probability p ≤ 1. The detailed-balance equation is satisfied if, in the Metropolis scheme, we take as the probability of acceptance of the Monte-Carlo move [18] …”

Section: Monte Carlo Movesmentioning

confidence: 99%

Monte Carlo simulations of star-branched polyelectrolyte micelles

et al. 2002

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Abstract. The concentration profiles of monomers and counterions in star-branched polyelectrolyte micelles are calculated through Monte-Carlo simulations, using the simplest freely-jointed chain model. We have investigated the onset of different regimes corresponding to the spherical and Manning condensation of counterions as a function of the strength of the Coulomb coupling. The Monte-Carlo results are in fair agreement with the predictions of Self-Consistent-Field analytical models. We have simulated a real system of diblock copolymer micelles of (sodium-polystyrene-sulfonate)(NaPSS)-(polyethylene-propylene)(PEP) with f=54 hydrophilic branches of N = 251 monomers at room temperature in salt-free solution and compared the calculated form factor with our neutron-scattering data.

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A ‘Partially Clothed’ Pivot Algorithm for Model Polyelectrolyte Solutions

Cited by 24 publications

References 60 publications

Modelling the interaction processes between nanoparticles and biomacromolecules of variable hydrophobicity: Monte Carlo simulations

Modelling the interaction processes between nanoparticles and biomacromolecules of variable hydrophobicity: Monte Carlo simulations

Influence of Explicit Ions on Titration Curves and Conformations of Flexible Polyelectrolytes: A Monte Carlo Study

Monte Carlo simulations of star-branched polyelectrolyte micelles

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