The shear flow behavior of LCPs based on a generalized Doi model with distortional elasticity

Sgalari, G.; Leal, Gary L.; Feng, James J.

doi:10.1016/s0377-0257(01)00187-2

Cited by 50 publications

(34 citation statements)

References 31 publications

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“…But they are limited by small sample sizes and nanoscopic length scales [12]. An additional advantage of the mean-field theory is that it is easily extendable to dynamic problems in complex geometry, such as are relevant, for example, to processing flows of liquid-crystalline polymers [18,28]. A limitation of the mean-field theory is that the Taylor expansion used in deriving Eq.…”

Section: Theoretical Model and Numerical Methodsmentioning

confidence: 99%

Orientational defects near colloidal particles in a nematic liquid crystal

Feng

Zhou

2004

Journal of Colloid and Interface Science

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Section: Theoretical Model and Numerical Methodsmentioning

confidence: 99%

Orientational defects near colloidal particles in a nematic liquid crystal

Feng

Zhou

2004

Journal of Colloid and Interface Science

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“…A characterization of the lengthscales in the molecular distribution responsible for the scattering patterns, and whether they are due to changes in the direction of peak orientation (nematic elasticity) or due to focusing and defocusing of the orientational distribution (molecular elasticity), are the subject of numerous modeling and computational studies (cf. [32,30,21,29]). Molecular orientation features in different flow regimes are of extreme importance for materials design, as they impart anisotropic and nonuniform material properties [34,18,19].…”

mentioning

confidence: 99%

On Weak Plane Couette and Poiseuille Flows of Rigid Rod and Platelet Ensembles

Cui¹,

Forest²,

Wang³

et al. 2006

SIAM J. Appl. Math.

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On weak plane Couette and Poiseuille flows of rigid rod and platelet ensembles (with Z. Cui, M.G. Forest and Q. Wang), SIAM J. Appl. Math. , 66 (4), 2006 Abstract. Films and molds of nematic polymer materials are notorious for heterogeneity in the orientational distribution of the rigid rod or platelet macromolecules. Predictive tools for structure length scales generated by shear-dominated processing are vitally important: both during processing because of flow feedback phenomena such as shear thinning or thickening, and postprocessing since gradients in the rod or platelet ensemble translate to nonuniform composite properties and to residual stresses in the material. These issues motivate our analysis of two prototypes for planar shear processing: drag-driven Couette and pressure-driven Poiseuille flows. Hydrodynamic theories for high aspect ratio rod and platelet macromolecules in viscous solvents are well developed, which we apply in this paper to model the coupling between short-range excluded volume interactions, anisotropic distortional elasticity (unequal elasticity constants), wall anchoring conditions, and hydrodynamics. The goal of this paper is to generalize scaling properties of steady flow molecular structures in slow Couette flows with equal elasticity constants [M. G. Forest et al., J. Rheol., 48 (2004), pp. 175-192] in several ways: to contrast isotropic and anisotropic elasticity; to compare Couette versus Poiseuille flow; and to consider dynamics and stability of these steady states within the asymptotic model equations.

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“…[17][18][19][20][21][22][23][24] Constitutive equations including long-range elastic interactions in the nematic potential were successfully applied to describe defect textures. 17,18) Tsuji and Rey 19) have numerically analyzed the shear flow of LC materials using a nonlinear and nonequilibrium theory including the short-and long-range order elasticity and viscous effects.…”

Section: Introductionmentioning

confidence: 99%

Numerical Simulation of Emergence of Textures in Flows of Liquid Crystalline Polymers using a Constitutive Model with Long-Range Elasticity

Yamamoto

Kimura

2008

J. Soc. Rheol., Jpn

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Simple shear and Poiseuille flows of liquid crystalline polymers between parallel plates were numerically simulated using the Marrucci-Greco model, which is a constitutive equation that includes long-range elasticity effects. Homogeneous, inhomogeneous decoupled, and inhomogeneous full coupled models [Kupferman et al., J Non-Newtonian Fluid Mech, 91, 255 (2000)] were considered in the present simulation. In the simulation of Poiseuille flows, the relation between the long-range elasticity and the emergence of textures caused by the distribution of orientation angle of directors was investigated. The molecular orientation on the channel plate restricts rotation of directors near the plate through the long-range elasticity, and irregular rotation motions of directors were observed in the inhomogeneous full coupled simulation. Full coupled computations of the velocity field and the director motion predicted the emergence of textures during flows. In addition, the simulation results suggested that a director rotation and the molecular interaction due to the long-range elasticity are necessary for the emergence of textures.

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The shear flow behavior of LCPs based on a generalized Doi model with distortional elasticity

Cited by 50 publications

References 31 publications

Orientational defects near colloidal particles in a nematic liquid crystal

Orientational defects near colloidal particles in a nematic liquid crystal

On Weak Plane Couette and Poiseuille Flows of Rigid Rod and Platelet Ensembles

Numerical Simulation of Emergence of Textures in Flows of Liquid Crystalline Polymers using a Constitutive Model with Long-Range Elasticity

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