Three-body interactions in complex fluids: Virial coefficients from simulation finite-size effects

The relevance of neglecting three- and four-body interactions in the coarse-grained version of the Asakura-Oosawa model is examined. A mapping between the first few virial coefficients of the binary nonadditive hard-sphere mixture representative of this model and those arising from the coarse-grained (pairwise) depletion potential approximation allows for a quantitative evaluation of the effect of such interactions. This turns out to be especially important for large size ratios and large reservoir polymer packing fractions.

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“…3 of Ref. 27. We observe that the impact of three-and four- Notwithstanding the results displayed in Figs.…”

Section: A Similar Conclusion Can Be Drawn From Bsupporting

confidence: 54%

The effective colloid interaction in the Asakura–Oosawa model. Assessment of non-pairwise terms from the virial expansion

Santos

Haro

Fiumara

et al. 2015

The Journal of Chemical Physics

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“…35,52,53 The method will allow analysis of phase behaviour in these systems, and also quantification of the effects of manybody interactions. 34 Similar questions arises in systems where the large particles are not spherical, in which case the depletion interaction has a more complicated charac-ter [54][55][56] and can lead to new phase behaviour. 55,57 There are also potential applications of the TL method to other soft matter systems including star polymers and dendrimers, for which accurate coarse-grained models are available, 1,58,59 and whose phase behaviour is rich and complex.…”

Section: Discussionmentioning

confidence: 94%

“…For the second term on the right hand side of (D4), one uses (20,34,41) to show that |Ê| ≤ a. Hence | Ê 1 {2( +1)≤1} | ≤ a Prob( ≤ −1/2).…”

Section: Appendix D: the Bias Of The Estimatorâmentioning

confidence: 99%

Correction of coarse-graining errors by a two-level method: Application to the Asakura-Oosawa model

Kobayashi

Rohrbach

Scheichl

et al. 2019

The Journal of Chemical Physics

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We present a method that exploits self-consistent simulation of coarse-grained and fine-grained models, in order to analyse properties of physical systems. The method uses the coarse-grained model to obtain a first estimate of the quantity of interest, before computing a correction by analysing properties of the fine system. We illustrate the method by applying it to the Asakura-Oosawa (AO) model of colloid-polymer mixtures. We show that the liquid-vapour critical point in that system is affected by three-body interactions which are neglected in the corresponding coarse-grained model. We analyse the size of this effect and the nature of the three-body interactions. We also analyse the accuracy of the method, as a function of the associated computational effort. arXiv:1907.07912v1 [cond-mat.stat-mech]

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“…If q < q 0 , the general relationship between the reservoir packing fraction η (r) s (or, equivalently, the fugacity z s ) and the values η s and η l of the binary mixture is derived in Appendix C with the result 20) where g eff (r|η l , η (r) s ) is the radial distribution function of a pure fluid of large particles interacting via the effective …”

Section: The Sao Modelmentioning

confidence: 99%

Bridging and depletion mechanisms in colloid-colloid effective interactions: A reentrant phase diagram

Fantoni

Giacometti

Santos

2015

The Journal of Chemical Physics

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A general class of nonadditive sticky-hard-sphere binary mixtures, where small and large spheres represent the solvent and the solute, respectively, is introduced. The solute-solute and solvent-solvent interactions are of hard-sphere type, while the solute-solvent interactions are of sticky-hard-sphere type with tunable degrees of size nonadditivity and stickiness. Two particular and complementary limits are studied using analytical and semi-analytical tools. The first case is characterized by zero nonadditivity, lending itself to a PercusYevick approximate solution from which the impact of stickiness on the spinodal curves and on the effective solute-solute potential is analyzed. In the opposite nonadditive case, the solvent-solvent diameter is zero and the model can then be reckoned as an extension of the well-known Asakura-Oosawa model with additional sticky solute-solvent interaction. This latter model has the property that its exact effective one-component problem involves only solute-solute pair potentials for size ratios such that a solvent particle fits inside the interstitial region of three touching solutes. In particular, we explicitly identify the three competing physical mechanisms (depletion, pulling, and bridging) giving rise to the effective interaction. Some remarks on the phase diagram of these two complementary models are also addressed through the use of the Noro-Frenkel criterion and a first-order perturbation analysis. Our findings suggest reentrance of the fluid-fluid instability as solvent density (in the first model) or adhesion (in the second model) is varied. Some perspectives in terms of the interpretation of recent experimental studies of microgels adsorbed onto large polystyrene particles are discussed.

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Three-body interactions in complex fluids: Virial coefficients from simulation finite-size effects

Cited by 20 publications

References 73 publications

The effective colloid interaction in the Asakura–Oosawa model. Assessment of non-pairwise terms from the virial expansion

The effective colloid interaction in the Asakura–Oosawa model. Assessment of non-pairwise terms from the virial expansion

Correction of coarse-graining errors by a two-level method: Application to the Asakura-Oosawa model

Bridging and depletion mechanisms in colloid-colloid effective interactions: A reentrant phase diagram

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