Theory of phase separation for a solution of tridisperse rod-like particles

Vroege, G. J.; Lekkerkerker, H. N. W.

doi:10.1016/s0927-7757(97)00058-7

Cited by 17 publications

(18 citation statements)

References 30 publications

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“…That, e.g., length polydispersity has significant effects on phase behaviour is clear from studies of bi-and tridisperse systems (two/three different rod lengths). For sufficiently disparate lengths coexistence of several nematic phases (N-N), possibly also together with an isotropic phase (I-N-N), is predicted [16][17][18][19][20][21] and has been observed experimentally [15]. The N-N region in the bidisperse phase diagram is terminated by a critical point for length ratios between around 2.9 and 3.2 [22] but is open towards large densities [18][19][20] for larger ratios.…”

Section: Application I: Hard Rods With Length Polydispersitymentioning

confidence: 76%

Phase equilibria in polydisperse colloidal systems

Fasolo

Sollich

Speranza

2004

Reactive and Functional Polymers

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Section: Application I: Hard Rods With Length Polydispersitymentioning

confidence: 76%

Phase equilibria in polydisperse colloidal systems

Fasolo

Sollich

Speranza

2004

Reactive and Functional Polymers

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“…Such an approach has also been described in the context of sphere‐like coiled polymers. Also, note that in certain polydisperse systems, nematic–nematic demixing of rods is possible as well;34, 35 this has been explored in some detail by Wensink and Vroege28 for sphere‐free systems similar to those studied here using a similar formulation. In this article, these issues of I–I or N–N demixing are not addressed because our principal interest is the influence of spheres on the I–N coexistence curves.…”

Section: Formulationmentioning

confidence: 89%

Isotropic–nematic phase separation and demixing in mixtures of spherical nanoparticles with length‐polydisperse nanorods

Green

2012

J Polym Sci B Polym Phys

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An extension of Onsager theory is developed to simulate isotropic–nematic phase separation in a mixture of spheres with length‐polydisperse system of rods. This work is motivated by recent experimental data on nanorod liquid crystals. Prior theoretical investigations indicate that both polydispersity and the presence of spheres should increase the biphasic–nematic phase transition, that is, the nematic cloud point. Results indicate that the phase diagrams undergo drastic changes depending upon both particle geometry and rod length polydispersity. The key geometric factor is the ratio between the sphere diameter and the rod diameter. In general, length fractionation is enhanced by the addition of spheres, which may be experimentally advantageous for separating short nanorods from a polydisperse population. Simulation results also indicate that the nematic cloud and shadow curves may cross one another because of the scarcity of spheres in the shadow phase. In general, these results do indicate that the nematic cloud point increases as a function of sphere loading; however, in certain areas of phase space, this relationship is nonmonotonic such that the nematic cloud point may actually decrease with the addition of spheres. This work has application to a wide range of nanoparticle systems, including mixtures of spherical nanoparticles with nanorods or nanotubes. Additionally, a number of nonspherical particles and structures may behave as spheres, including crumpled graphene and tightly coiled polymers. © 2012 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys, 2012

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“…5,6 The issue of polydispersity and its effect on the interpretation of experimental results has already been addressed by Onsager in his original paper. Later on, extensions of the Onsager theory allowing for phase diagram calculations for bidisperse [7][8][9][10][11][12] and tridisperse systems 13 of hard rods as well as binary mixtures of hard platelets 14 revealed a rich variety in behavior, most notably a widening of the coexistence region, a fractionation effect ͑i.e., segregation of the species among the coexisting phases͒, a reentrant phenomenon and, most interestingly, the possibility of a demixing of the nematic phase which may give rise to isotropic-nematic-nematic triphasic equilibria.…”

Section: Introductionmentioning

confidence: 99%

Isotropic–nematic phase behavior of length-polydisperse hard rods

Wensink

Vroege

2003

The Journal of Chemical Physics

103

124

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Articles you may be interested inQuenched-annealed density functional theory for interfacial behavior of hard rods at a hard rod matrix Phase coexistence in polydisperse multi-Yukawa hard-sphere fluid: High temperature approximation Isotropic-nematic phase equilibria of polydisperse hard rods: The effect of fat tails in the length distributionThe isotropic-nematic phase behavior of length-polydisperse hard rods with arbitrary length distributions is calculated. Within a numerical treatment of the polydisperse Onsager model using the Gaussian trial function ansatz we determine the onset of isotropic-nematic phase separation, coming from a dilute isotropic phase and a dense nematic phase. We focus on parent systems whose lengths can be described by either a Schulz or a ''fat-tailed'' log-normal distribution with appropriate lower and upper cutoff lengths. In both cases, very strong fractionation effects are observed for parent polydispersities larger than roughly 50%. In these regimes, the isotropic and nematic phases are completely dominated by, respectively, the shortest and the longest rods in the system. Moreover, for the log-normal case, we predict triphasic isotropic-nematic-nematic equilibria to occur above a certain threshold polydispersity. By investigating the properties of the coexisting phases across the coexistence region for a particular set of cutoff lengths we show that the region of stable triphasic equilibria does not extend up to very large parent polydispersities but closes off at a consolute point located not far above the threshold polydispersity. The experimental relevance of the phenomenon is discussed.

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Theory of phase separation for a solution of tridisperse rod-like particles

Cited by 17 publications

References 30 publications

Phase equilibria in polydisperse colloidal systems

Phase equilibria in polydisperse colloidal systems

Isotropic–nematic phase separation and demixing in mixtures of spherical nanoparticles with length‐polydisperse nanorods

Isotropic–nematic phase behavior of length-polydisperse hard rods

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