Many-body interactions and correlations in coarse-grained descriptions of polymer solutions

Bolhuis, Peter G.; Louis, Ard A.; Hansen, Jean‐Pierre

doi:10.1103/physreve.64.021801

Cited by 82 publications

(139 citation statements)

References 61 publications

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“…It can also lead to a second liquid-liquid phase separation in systems that already show a gas-liquid phase-coexistence [36]. A broad discussion of density-dependent pair-potentials with many illustrative examples of typical soft-matter systems is given by Louis [37], including recent theoretical studies of coarse graining of polymers as 'soft colloids' [38,39]. Louis points out that the effective density-dependent pair potential in eq.…”

Section: Many-body Interactions and Density-dependent Pair-potentmentioning

confidence: 99%

Many-body interactions and the melting of colloidal crystals

Dobnikar

Chen

Rzehak

et al. 2003

The Journal of Chemical Physics

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We study the melting behavior of charged colloidal crystals, using a simulation technique that combines a continuous mean-field Poisson-Boltzmann description for the microscopic electrolyte ions with a Brownian-dynamics simulation for the mesoscopic colloids. This technique ensures that many-body interactions between the colloids are fully taken into account, and thus allows us to investigate how many-body interactions affect the solid-liquid phase behavior of charged colloids.Using the Lindemann criterion, we determine the melting line in a phase-diagram spanned by the colloidal charge and the salt concentration. We compare our results to predictions based on the established description of colloidal suspensions in terms of pairwise additive Yukawa potentials, and find good agreement at high-salt, but not at low-salt concentration. Analyzing the effective pairinteraction between two colloids in a crystalline environment, we demonstrate that the difference in the melting behavior observed at low salt is due to many-body interactions. If the salt concentration is high, we find configuration-independent pair-forces of perfect Yukawa form with effective charges and screening constants that are in good agreement with well-established theories. At low added salt, however, the pair-forces are Yukawa-like only at short distances with effective parameters that depend on the analyzed colloidal configuration. At larger distances, in contrast, the pair-forces decay to zero much faster than they would following a Yukawa force law. This is explained with a screening effect of the macroions. Based on these findings, we suggest a simple model potential for colloids in suspension which has the form of a Yukawa potential, truncated after the first coordination shell of a colloid in a crystal. Using this potential in a one-component simulation, we find a melting line that shows good agreement with the one derived from the full PoissonBoltzmann-Brownian-dynamics simulation.2

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Section: Many-body Interactions and Density-dependent Pair-potentmentioning

confidence: 99%

Many-body interactions and the melting of colloidal crystals

Dobnikar

Chen

Rzehak

et al. 2003

The Journal of Chemical Physics

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“…It thus seems natural to attempt the same for the polymers. We have recently succeeded in modeling linear polymers as "soft colloids" [38][39][40][41]56 , where each polymer is replaced by a single particle centered on its CM. Different coils interact via an effective pair potential acting between their CM.…”

Section: F Polymers As Soft Colloidsmentioning

confidence: 99%

“…We derive the scaling behavior with density, and find important deviations from the AO model and other ideal-polymer theories. We also calculate the depletion potential between spheres within our new "polymers as soft colloids" coarsegraining scheme [38][39][40][41] , where each polymer is represented by a single particle, interacting via a density-dependent effective potential. Here we again find good agreement with the direct MC results for the dilute regime, but for ρ/ρ * > 2, significant deviations are found.…”

Section: Introductionmentioning

confidence: 99%

Polymer induced depletion potentials in polymer-colloid mixtures

Louis

Bolhuis

Meijer

et al. 2002

The Journal of Chemical Physics

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151

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The depletion interactions between two colloidal plates or between two colloidal spheres, induced by interacting polymers in a good solvent, are calculated theoretically and by computer simulations. A simple analytical theory is shown to be quantitatively accurate for case of two plates. A related depletion potential is derived for two spheres; it also agrees very well with direct computer simulations. Theories based on ideal polymers show important deviations with increasing polymer concentration: They overestimate the range of the depletion potential between two plates or two spheres at all densities, with the largest relative change occurring in the dilute regime. They underestimate the well depth at contact for the case of two plates, but overestimate it for two spheres. Depletion potentials are also calculated using a coarse graining approach which represents the polymers as "soft colloids": good agreement is found in the dilute regime. Finally, the effect of the polymers on colloid-colloid osmotic virial coefficients is related to phase behavior of polymer-colloid mixtures.

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“…In the former case, the number densities of the two components are constrained by the electroneutrality condition. In the latter, where one specific monomer [12,13] or the centre of mass of the molecule [14,15,16,17,18] are chosen as effective, mesoscopic coordinates, the total number of monomers and the number of effective particles are coupled to each other through the constraint of keeping the number of monomers per macromolecule fixed.…”

Section: Introductionmentioning

confidence: 99%

Microscopic and coarse-grained correlation functions of concentrated dendrimer solutions

Götze¹,

Likos²

2005

J. Phys.: Condens. Matter

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Abstract. We employ monomer-resolved computer simulations of model dendrimer molecules, to examine the significance of many-body effects in concentrated solutions of the same. In particular, we measure the radial distribution functions and the scattering functions between the centres of mass of the dissolved dendrimers at various concentrations, reaching values that slightly exceed the overlap density of the macromolecules. We analyse the role played by many-body effective interactions by comparing the structural data to those obtained by applying exclusively the previously obtained two-body effective interactions between the dendrimers [Götze I O, Harreis H M and Likos C N 2004 J. Chem. Phys. 120 7761]. We find that the effects of the many-body forces are small in general and they become weaker as the dendrimer flexibility increases. Moreover, we test the validity of the oft-used factorisation approximation to the total scattering intensity into a product of the form-and the scattering factors, finding a breakdown of this factorisation at high concentrations.

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Many-body interactions and correlations in coarse-grained descriptions of polymer solutions

Cited by 82 publications

References 61 publications

Many-body interactions and the melting of colloidal crystals

Many-body interactions and the melting of colloidal crystals

Polymer induced depletion potentials in polymer-colloid mixtures

Microscopic and coarse-grained correlation functions of concentrated dendrimer solutions

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