Erratum: “A theory for flowing nematic polymers with orientational distortion” [J. Rheol. 44, 1085–1101 (2000)]

Feng, James J.; Sgalari, G.; Leal, Lyndsay

doi:10.1122/1.1323466

Cited by 8 publications

(9 citation statements)

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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%

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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%

“…(1), an evolution equation can be derived for A subject to flow, Brownian motion and nematic interactions [17,18],…”

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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“…Computation of LCP structural dynamics during processing is a difficult task. Although progress has been made in using molecular‐scale models to predict detailed microscopic phenomena in simple flows [12–15], it is unfeasible to apply these theories to realistic processing flows. Building on recent efforts [4], in this work, we employ the “polydomain” model of Larson and Doi [16], based on the linear Leslie–Ericksen theory [17].…”

Section: Introductionmentioning

confidence: 99%

Molecular orientation distributions during injection molding of liquid crystalline polymers: Ex situ investigation of partially filled moldings

Fang¹,

Burghardt

Bubeck

2011

Polymer Engineering & Sci

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The development of molecular orientation in thermotropic liquid crystalline polymers (TLCPs) during injection molding has been investigated using two‐dimensional wide‐angle X‐ray scattering coordinated with numerical computations employing the Larson–Doi polydomain model. Orientation distributions were measured in “short shot” moldings to characterize structural evolution prior to completion of mold filling, in both thin and thick rectangular plaques. Distinct orientation patterns are observed near the filling front. In particular, strong extension at the melt front results in nearly transverse molecular alignment. Far away from the flow front shear competes with extension to produce complex spatial distributions of orientation. The relative influence of shear is stronger in the thin plaque, producing orientation along the filling direction. Exploiting an analogy between the Larson–Doi model and a fiber orientation model, we test the ability of process simulation tools to predict TLCP orientation distributions during molding. Substantial discrepancies between model predictions and experimental measurements are found near the flow front in partially filled short shots, attributed to the limits of the Hele–Shaw approximation used in the computations. Much of the flow front effect is however “washed out” by subsequent shear flow as mold filling progresses, leading to improved agreement between experiment and corresponding numerical predictions. POLYM. ENG. SCI.,, 2011. © 2011 Society of Plastics Engineers

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“…These orientation structures are mainly formed in the process, where the melt materials flow into dies, and remain in the final products. For the last few decades, many researches have been performed on the molecular orientation in the LCP flows, especially by means of theoretical and computational analysis 1–5. One of the major advances in the theoretical LCP rheology was made by Doi in 1981, who extended the theory for semidilute polymeric fluids to that for concentrated rod‐like polymeric fluids.…”

Section: Introductionmentioning

confidence: 99%

“…For the last few decades, many researches have been performed on the molecular orientation in the LCP flows, especially by means of theoretical and computational analysis. [1][2][3][4][5] One of the major advances in the theoretical LCP rheology was made by Doi in 1981, who extended the theory for semidilute polymeric fluids to that for concentrated rod-like polymeric fluids. For simple shear, the exact solutions of the Doi theory showed that at low shear rates the orientation distribution function displayed a time-periodic tumbling, followed by the steady-state or flow-aligning, where the director became stationary at high shear rates.…”

Section: Introductionmentioning

confidence: 99%

On the flow‐phase diagram for nematic liquid crystalline polymer under magnetic field

Bai

2009

J of Applied Polymer Sci

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The effect of magnetic fields on molecular configuration of liquid crystalline polymers under shear flows are numerically analyzed using the extended Doi theory in which a molecular shape parameter is admitted. The evolution equation for the probability density function of the LCP molecules is directly solved without any closure approximations. One case is considered that the magnetic field makes 45 with respect to the flow direction. We can find that the magnetic fields strongly affect on the transition among flow-orientation modes, such as tumbling, wagging, and aligning modes. And a new aligning flow-orientation mode emerges at low shear rate, which is macroscopically same as the ordinary aligning mode, but is microscopically quite different from the ordinary one.

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Erratum: “A theory for flowing nematic polymers with orientational distortion” [J. Rheol. 44, 1085–1101 (2000)]

Cited by 8 publications

References 0 publications

Orientational defects near colloidal particles in a nematic liquid crystal

Orientational defects near colloidal particles in a nematic liquid crystal

Molecular orientation distributions during injection molding of liquid crystalline polymers: Ex situ investigation of partially filled moldings

On the flow‐phase diagram for nematic liquid crystalline polymer under magnetic field

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