Communication: Thermodynamic signatures of cluster formation in fluids with competing interactions

Bomont, Jean‐Marc; Bretonnet, Jean-Louis; Costa, Dino; Hansen, Jean‐Pierre

doi:10.1063/1.4733390

Cited by 50 publications

(42 citation statements)

References 21 publications

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“…In order to shed light on this scenario, we make use of the RISM theory of molecular liquids which, together with the Ornstein-Zernike integral equation description of atomic fluids [55], has been already adopted in previous studies to characterize the onset of aggregates in non-homogenous fluids [60][61][62]. In Figure 4 we compare RISM and MC results for g 22 (r) [panel (a)] and S 22 (k) [panel (b)] at fixed T = 0.005.…”

Section: Resultsmentioning

confidence: 99%

Evidence of Structural Inhomogeneities in Hard-Soft Dimeric Particles without Attractive Interactions

Munaò

Saija

2019

Materials

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We perform Monte Carlo simulations of a simple hard-soft dimeric model constituted by two tangent spheres experiencing different interactions. Specifically, two hard spheres belonging to different dimers interact via a bare hard-core repulsion, whereas two soft spheres experience a softly repulsive Hertzian interaction. The cross correlations are soft as well. By exploring a wide range of temperatures and densities we investigate the capability of this model to document the existence of structural inhomogeneities indicating the possible onset of aggregates, even if no attraction is set. The fluid phase behavior is studied by analyzing structural and thermodynamical properties of the observed structures, in particular by computing radial distribution functions, structure factors and cluster size distributions. The numerical results are supported by integral equation theories of molecular liquids which allow for a finer and faster spanning of the temperature-density diagram. Our results may serve as a framework for a more systematic investigation of self-assembled structures of functionalized hard-soft dimers able to aggregate in a variety of structures widely oberved in colloidal dispersion.

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Section: Resultsmentioning

confidence: 99%

Evidence of Structural Inhomogeneities in Hard-Soft Dimeric Particles without Attractive Interactions

Munaò

Saija

2019

Materials

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“…However, for the system considered in Ref. 9, discontinuities in thermodynamic quantities were observed at the onset of cluster formation, suggesting it is indeed a phase transition.…”

Section: Introductionmentioning

confidence: 98%

Two-dimensional colloidal fluids exhibiting pattern formation

Chacko

Chalmers

Archer

2015

The Journal of Chemical Physics

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Hard sphere fluids at a soft repulsive wall: A comparative study using Monte Carlo and density functional methods J. Chem. Phys. 134, 214706 (2011) Fluids with competing short range attraction and long range repulsive interactions between the particles can exhibit a variety of microphase separated structures. We develop a lattice-gas (generalised Ising) model and analyse the phase diagram using Monte Carlo computer simulations and also with density functional theory (DFT). The DFT predictions for the structures formed are in good agreement with the results from the simulations, which occur in the portion of the phase diagram where the theory predicts the uniform fluid to be linearly unstable. However, the mean-field DFT does not correctly describe the transitions between the different morphologies, which the simulations show to be analogous to micelle formation. We determine how the heat capacity varies as the model parameters are changed. There are peaks in the heat capacity at state points where the morphology changes occur. We also map the lattice model onto a continuum DFT that facilitates a simplification of the stability analysis of the uniform fluid. C 2015 AIP Publishing LLC. [http://dx

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“…This is true at the least upon specific thermodynamic conditions and 2Y parameterizations. 48,49 Having discussed the importance of a careful scrutiny of structural correlations in the wavelength regime associated with the IRO peak, we tackle this issue via an analytical treatment of a standard Hard-Sphere Two-Yukawa (HS2Y) potential, based on the Random Phase Approximation (RPA). 14 We first document the reasonable accuracy of this theoretical scheme in predicting the structural properties, as assessed against exact Monte Carlo results.…”

Section: Introductionmentioning

confidence: 99%

A semianalytical “reverse” approach to link structure and microscopic interactions in two-Yukawa competing fluids

Bretonnet

Bomont

Costa

2018

The Journal of Chemical Physics

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We study theoretically a prototype hard-sphere two-Yukawa model with competing interactions, under thermodynamic conditions associated with the formation of clusters. We adopt the analytically solvable random phase approximation and show that this theory predicts reasonably well the structure of the fluid-in comparison with exact Monte Carlo results-within a unique parameterization of the direct correlation function inside the hard core of particles. In particular, the theory follows correctly the development, in the structure factor, of a local peak at low wavevectors, as peculiarly associated with the onset of aggregation. We then model the direct correlation function in the same wavevector regime by a Gaussian function, so as to systematically investigate, in a "reverse" scheme, how varying the properties of the local peak modifies the original underlying competing interaction. We show that large variations in the height of the peak are generally associated with comparatively smaller variations in the height of the microscopic repulsive barrier; moreover, the shrinking and shifting towards lower wavevectors of the peak may be interpreted in terms of the displacement of the barrier, producing a substantial enlargement of the range of both the attractive and repulsive contributions to the interaction potential. Finally, we document the way the repulsive barrier tends to vanish as the two-Yukawa fluid approaches a "simple fluid" behavior, heralding the onset of a liquid-vapor phase separation. Published by AIP Publishing. https://doi.

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Communication: Thermodynamic signatures of cluster formation in fluids with competing interactions

Cited by 50 publications

References 21 publications

Evidence of Structural Inhomogeneities in Hard-Soft Dimeric Particles without Attractive Interactions

Evidence of Structural Inhomogeneities in Hard-Soft Dimeric Particles without Attractive Interactions

Two-dimensional colloidal fluids exhibiting pattern formation

A semianalytical “reverse” approach to link structure and microscopic interactions in two-Yukawa competing fluids

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