A quasichemical lattice model for a binary mixture of hard rectangular parallelepipeds Application to systems composed of nematic and non-mesogenic molecules

Sokolova, E. P.; Vlasov, A. Yu.

doi:10.1080/02678299008047329

Cited by 12 publications

(7 citation statements)

References 20 publications

(16 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The interaction free energy is of the form given in eq 5. When evaluating the integral over positions and orientations of particles, the orientational lattice approximation (see, e.g., ref ) is used, in which particle orientations are restricted to being along the x , y , or z directions only. This approximation is necessary to reduce the number of degrees of freedom and thus make it possible to analyze the whole phase diagram within a reasonable time frame.…”

Section: Resultsmentioning

confidence: 99%

Calculating Phase Diagrams of Polymer−Platelet Mixtures Using Density Functional Theory: Implications for Polymer/Clay Composites

1999

View full text Add to dashboard Cite

We analyze the thermodynamics of disklike particles dispersed in a polymer matrix. Using the Somoza−Tarazona free energy functional for thin oblate ellipsoids of revolution in combination with the Flory−Huggins mixing free energy, we obtain a new expression that allows us to describe the complete (liquid, crystalline, and liquid crystalline) phase diagram for the mixture as a function of shape anisotropy κ, polymer chain length N, and the disk−disk interaction parameter, q. It is shown that at large q and/or N positional ordering plays an important role in determining the stability and morphology of such mixtures.

show abstract

Section: Resultsmentioning

confidence: 99%

Calculating Phase Diagrams of Polymer−Platelet Mixtures Using Density Functional Theory: Implications for Polymer/Clay Composites

1999

View full text Add to dashboard Cite

show abstract

“…When evaluating the integral over positions and orientations of particles (the rhs of eq 11), we use the orientational lattice approximation (see, e.g., ref ). In this approach, particle orientations are restricted to being along the x , y , or z directions only.…”

Section: Theorymentioning

confidence: 99%

Theoretical Phase Diagrams of Polymer/Clay Composites: The Role of Grafted Organic Modifiers

2000

View full text Add to dashboard Cite

We combine a density functional theory (DFT) with a self-consistent field model (SCF) to calculate the phase behavior of thin, oblate colloidal particles that are coated with surfactants and dispersed in a polymer melt. These coated particles represent organically modified clay sheets. By integrating the two methods, we can investigate the effect of the surfactants' characteristics (grafting density F gr and length Ngr) and the polymer-surfactant interaction energy on the polymer-clay phase diagram. Depending on the values of these critical parameters and the clay volume fraction, φ, the system can be in an isotropic or nematic phase (which corresponds to an exfoliated composite). The system can also form a smectic, crystal, columnar, or "house-of-cards" plastic solid, as well as a two-phase (immiscible) mixture. Using this model, we isolate conditions that lead to the stabilization of the homogeneous, exfoliated phases (the isotropic and nematic regions) and to the narrowing of the immiscible two-phase regions.

show abstract

“…The ordering of principal axes of uniaxial particles with respect to n is defined in terms of statistical averages [1,4,12,14]:…”

Section: The Molecular-thermodynamic Frameworkmentioning

confidence: 99%

“…For a particular case of a system composed of uniaxial blocks, the lattice model results are shown to be identical to those of Mitra and Allnatt [13] who utilized the so-called complete star approximation based on the summation of Mayer full stars in the virial expansion of the configurational entropy. The quasichemical treatment of attractive interactions carried out in reference [14] indicated that the lattice approach offers considerable latitude as a formal structure suitable for correlating orientational and thermodynamic functions of some real nematic mixtures.…”

Section: Introductionmentioning

confidence: 99%

Orientational and thermodynamic properties of rod - plate mixtures

Sokolova¹,

Vlasov²

1997

J. Phys.: Condens. Matter

View full text Add to dashboard Cite

The molecular-statistical model of a fluid composed of rectangular parallelepipeds, that is continuous in translations and discrete in orientation distribution, is employed in calculations relating to regions corresponding to the stability of uniaxial and biaxial nematic phases in model mixtures of uniaxial rod-like and plate-like particles, interacting via steric repulsion. The calculations are performed taking into account three-particle correlations. It is shown that for fixed overall mole fraction, the value of the configurational Gibbs free energy of a biaxial phase is equal to that of a system with a miscibility gap containing two uniaxial nematic phases, one rich in rod-like molecules and the other in plate-like ones. The results of the present study are compared with those of studies of related model systems.

show abstract

A quasichemical lattice model for a binary mixture of hard rectangular parallelepipeds Application to systems composed of nematic and non-mesogenic molecules

Cited by 12 publications

References 20 publications

Calculating Phase Diagrams of Polymer−Platelet Mixtures Using Density Functional Theory: Implications for Polymer/Clay Composites

Calculating Phase Diagrams of Polymer−Platelet Mixtures Using Density Functional Theory: Implications for Polymer/Clay Composites

Theoretical Phase Diagrams of Polymer/Clay Composites: The Role of Grafted Organic Modifiers

Orientational and thermodynamic properties of rod - plate mixtures

Contact Info

Product

Resources

About