Structure and thermodynamics of platelet dispersions

Harnau, Ludger

doi:10.1080/00268970802032301

Cited by 44 publications

(42 citation statements)

References 182 publications

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“…A distinctive feature is the non-monotonic behavior of orientational disorder-order transition with κσ. While for the fairly isotropic case with κσ = 1, the orientationally ordered phases appear at lower densities than those of hard disks [41,42], for κσ ≥ 2 the liquid-crystalline phases of charged disks appear at densities ρ * ≥ 4.5. In Fig.…”

Section: A Phase Behaviormentioning

confidence: 99%

Interplay of anisotropy in shape and interactions in charged platelet suspensions

Jabbari-Farouji

Weis

Levitz

et al. 2014

The Journal of Chemical Physics

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Motivated by the intriguing phase behavior of charged colloidal platelets, we investigate the structure and dynamics of charged repulsive disks by means of Monte-Carlo simulations. The electrostatic interactions are taken into account through an effective two-body potential, obtained within the nonlinear Poisson-Boltzmann formalism, which has the form of anisotropic screened Coulomb potential. Recently, we showed that the original intrinsic anisotropy of the electrostatic potential in competition with excluded volume effects leads to a rich phase behavior that not only includes various liquid-crsytalline phases but also predicts the existence of novel structures composed of alternating nematic-antinematic sheets. Here, we examine the structural and dynamical signatures of each of the observed structures for both translational and rotational degrees of freedom. Finally, we discuss the influence of effective charge value and our results in relation to experimental findings on charged platelet suspensions.

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Section: A Phase Behaviormentioning

confidence: 99%

Interplay of anisotropy in shape and interactions in charged platelet suspensions

Jabbari-Farouji

Weis

Levitz

et al. 2014

The Journal of Chemical Physics

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“…A similar approach was followed by Zhang et al accounting for finite platelet thickness, and incorporating the columnar phase [51,52]. Alternative approaches regarding platelet-sphere mixtures have also reported such isostructural coexistences [53,54]. Aliabadi et al [55] presented a stability overview for hard platelets plates in a sea of hard spheres.…”

Section: Introductionmentioning

confidence: 99%

Depletion-driven four-phase coexistences in discotic systems

et al. 2018

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Free volume theory (FVT) is a versatile and tractable framework to predict the phase behaviour of mixtures of platelets and non-adsorbing polymer chains in a common solvent. Within FVT, three principal reference phases for the hard platelets are considered: isotropic (I), nematic (N) and columnar (C). We derive analytical expressions that enable us to systematically trace the different types of phase coexistences revealed upon adding depletants and confirm the predictive power of FVT by testing the calculated diagrams against phase stability scenarios from computer simulation. A wide range of multi-phase equilibria is revealed, involving two-phase isostructural transitions of all phase symmetries (INC) considered as well as the possible three-phase coexistences. Moreover, we identify the system parameters, relative disk shapes and colloid-polymer size ratios, at which four-phase equilibria are expected. These involve a remarkable coexistence of all three-phase states commonly encountered in discotics including isostructural coexistences I 1 -I 2 -N-C, I-N 1 -N 2 -C and I-N-C 1 -C 2 .

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“…Real platelets differ from this simple model in many aspects: they vary in shape, are in general not very rigid and often even crumpled, are polydisperse in size, and their interactions are more complex than simple excluded volume interaction (see, e.g., [2,4,[17][18][19]). There are two common features, however: in almost all cases the platelets cannot interpenetrate each other and they have high aspect ratios.…”

Section: Simulation Detailsmentioning

confidence: 99%

Connectivity percolation in suspensions of hard platelets

2012

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We present a study on connectivity percolation in suspensions of hard platelets by means of Monte Carlo simulation. We interpret our results using a contact-volume argument based on an effective single-particle cell model. It is commonly assumed that the percolation threshold of anisotropic objects scales as their inverse aspect ratio. While this rule has been shown to hold for rodlike particles, we find that for hard platelike particles the percolation threshold is nonmonotonic in the aspect ratio. It exhibits a shallow minimum at intermediate aspect ratios and then saturates to a constant value. This effect is caused by the isotropic-nematic transition preempting the percolation transition. Hence the common strategy to use highly anisotropic, conductive particles as fillers in composite materials in order to produce conduction at low filler concentration is expected to fail for platelike fillers such as graphene and graphite nanoplatelets.

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Structure and thermodynamics of platelet dispersions

Cited by 44 publications

References 182 publications

Interplay of anisotropy in shape and interactions in charged platelet suspensions

Interplay of anisotropy in shape and interactions in charged platelet suspensions

Depletion-driven four-phase coexistences in discotic systems

Connectivity percolation in suspensions of hard platelets

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