Monte Carlo study of Widom-Rowlinson interface

Malijevský, Al.; Sokołowski, S.

doi:10.1063/1.2710251

Cited by 5 publications

(6 citation statements)

References 15 publications

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“…The latter value is to be compared with the values 0.431͑4͒ and 0.418͑9͒ obtained for systems containing N = 1500 ͑L / = 7.368͒ and N = 4000 ͑L / =10͒ particles, respectively ͑see TableIII͒. Our values of the interfacial tension appear to be consistent with ͑but slightly lower than͒ those obtained by Malijevský and Sokolowski20 in their recent study. An additional series of simulations are performed to analyze any possible dependence of the computed values…”

supporting

confidence: 85%

“…Theoretical approaches to the study of the bulk and interfacial behavior of the WR mixture include the use of the meanfield approximation, 3,[6][7][8][9] the virial expansion, 10 integral equations, [11][12][13][14] and classical density functional theory. 15 The results of computer simulations of the WR model have been reported, 11,12,[16][17][18][19] with a focus on the coexistence properties and critical behavior of the model, apart from the recent note by Malijevský and Sokolowski 20 who studied the fluid interface of the mixture by Monte Carlo.…”

Section: Introductionmentioning

confidence: 99%

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Surface tension of the Widom-Rowlinson model

Miguel

Almarza

Jackson

2007

The Journal of Chemical Physics

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We consider the computation of the surface tension of the fluid-fluid interface for the Widom-Rowlinson [J. Chem. Phys. 52, 1670 (1970)] binary mixture from direct simulation of the inhomogeneous system. We make use of the standard mechanical route, in which the surface tension follows from the computation of the normal and tangential components of the pressure tensor of the system. In addition to the usual approach, which involves simulations of the inhomogeneous system in the canonical ensemble, we also consider the computation of the surface tension in an ensemble where the pressure perpendicular (normal) to the planar interface is kept fixed. Both approaches are seen to provide consistent values of the interfacial tension. The issue of the system-size dependence of the surface tension is addressed. In addition, simulations of the fluid-fluid coexistence properties of the mixture are performed in the semigrand canonical ensemble. Our results are compared with existing data of the Widom-Rowlinson mixture and are also examined in the light of the vapor-liquid equilibrium of the thermodynamically equivalent one-component penetrable sphere model.

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confidence: 85%

Section: Introductionmentioning

confidence: 99%

Surface tension of the Widom-Rowlinson model

Miguel

Almarza

Jackson

2007

The Journal of Chemical Physics

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“…Above a critical density this system exhibits a demixing transition which makes it an attractive model for studying interfacial phenomena despite its simplicity. 31,32,33 It should be noted that due to its simplicity this model neglects many effects, such as dispersion or electrostatic interactions, that are present in experimental systems. However, this choice of this model allows us to isolate the effect of interfacial and capillary forces.…”

Section: Simulation Model and Methodologymentioning

confidence: 99%

Stability of Janus nanoparticles at fluid interfaces

Cheung

Bon

2009

Soft Matter

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Using Monte Carlo simulations the interaction of a nanometre-sized, spherical Janus particle (a particle with two distinct surface regions of different functionality, in this case showing amphiphilic behaviour) with an ideal fluid interface is studied. In common with previous simulations of spherical, isotropic particles, the range of the nanoparticle-interface interaction is significantly larger than the nanoparticle radius due to the broadening of the interface due to capillary waves. For a uniform particle (an isotropic particle with one surface characteristic) the stability of the particle at a liquid interface is decreased as the affinity for one liquid phase is increased relative to the other; for large affinity differences the detachment energies calculated from continuum theory become increasingly accurate. For a symmetric Janus particle (where the two different surface regions are of equal area), the presence of the particle at the interface becomes more stable upon increasing the difference in affinity between the two faces, with each face having a high affinity for the respective liquid phase. In the case studied here, where surface tension between the A-region of the particle with the A-component is identical to the surface tension between the B-region and B-component, the interaction is symmetric with respect to the nanoparticle interface separation. The particle is found to have a large degree of orientational freedom, in sharp contrast to micrometre-sized colloidal particles. Comparison with continuum theory shows that this significantly overestimates the detachment energy, due to its neglect of nanoparticle rotation; simulations of nanoparticles with fixed orientations show a considerably larger detachment energy. As the areas of the surface regions become asymmetric the stability of the Janus nanoparticle is decreased and, in the case of large differences in affinities of the two faces, the difference between detachment energies from simulation and continuum theory diminishes.

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“…It should be noted that this model neglects electrostatic and attractive van der Waals interactions present in real systems. However, due to its simplicity it is an attractive model for studying interfaces and a number of recent studies [25][26][27] have investigated its phase behavior and interfacial properties. The nanoparticle is modeled as a hard sphere of radius R c ¼ 1:5 to R c ¼ 3; the fluidnanoparticle interaction is identical for both components.…”

mentioning

confidence: 99%

“…The effect of capillary waves gives the interface a finite width w. This may be found from the decay of the solvent density profiles (averaged over the simulations), with w ¼ À½xðZÞ À xðÀZÞf dxðzÞ dz g À1 z¼z 0 [26], where xðzÞ ¼ 1 ðzÞ= ½ 1 ðzÞ þ 2 ðzÞ and xðAEZÞ are the average bulk compositions away from the interface (Z ¼ 10). The calculated values of , 12 , and w are listed in Table I and are in good agreement with previously calculated values [25,26].…”

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confidence: 99%

Interaction of Nanoparticles with Ideal Liquid-Liquid Interfaces

Cheung

Bon

2009

Phys. Rev. Lett.

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Using molecular simulations the interaction between a noncharged nanoparticle and an ideal liquid-liquid interface is studied. The free energy profile as function of nanoparticle-interface separation is determined using Wang-Landau sampling. Comparison between the simulation results and macroscopic theories shows that the latter give a poor description of the free energy profile. In particular, they underestimate both the range of interaction between the particle and the interface and its strength, with the discrepancy lessening as the particle radius increases. On increasing the solvent chemical potential the interaction strength increases and the interaction range decreases due to the increase in interfacial tension and consequent decrease in interfacial width.

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Monte Carlo study of Widom-Rowlinson interface

Abstract: We report the results of Monte Carlo investigations of the structure and the interfacial tension of the liquid-liquid interface of the Widom-Rowlinson mixture. The results are compared with a mean-field theory.

Cited by 5 publications

References 15 publications

Surface tension of the Widom-Rowlinson model

Surface tension of the Widom-Rowlinson model

Stability of Janus nanoparticles at fluid interfaces

Interaction of Nanoparticles with Ideal Liquid-Liquid Interfaces

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