Skip to main content
SpringerLink
Log in

Microstructural lattice simulation and transient rheological behavior of a flow-aligning liquid crystalline polymer under low shear rates

  • Published:
Korean Journal of Chemical Engineering Aims and scope Submit manuscript

Abstract

A microstructural lattice simulation for textured liquid crystalline polymer is carried out to predict rheological behavior, especially the stress evolution after shear inception. It is based on a combination of two main concepts: (i) the director in each cell of a supramolecular lattice has an orientation described by the minimization of total energy of director map, and (ii) the torque balance of each director under shear flow and anisotropic relaxational shear moduli depends on the averaged orientation of the director map. By considering the interaction between the nearestneighbor directors, the spatial orientational correlation is introduced and the spatial heterogeneity, i.e., a polydomain texture, is generated simultaneously. For the start-up shear flow, the overshoot and the steady value of shear stress increase and the former shifts toward a shorter time as the applied shear rate increases. Also, the calculated stress evolution is compared with the experimental result of a thermotropic liquid crystalline poly(ester-imide).

This is a preview of subscription content, log in via an institution to check access.

Access this article

Log in via an institution

Price excludes VAT (USA)
Tax calculation will be finalised during checkout.

Instant access to the full article PDF.

Institutional subscriptions

Similar content being viewed by others

References

  • Alderman, N. J. and Mackley, M. R., “Optical Textures Observed during the Shearing of Thermotropic Liquid-crystalline Polymers”,Faraday Disc. Chem. Soc.,79, 149 (1985).

    Article  CAS  Google Scholar 

  • Asada, T., Muramastsu, H., Watanabe, R. and Onogi, S., “Rheooptical Studies of Racemic Poly(γ-benzyl glutamate) Liquid Crystals”,Macromolecules,13, 867 (1980).

    Article  CAS  Google Scholar 

  • Assender, H. E. and Windle, A. H., “Two-dimensional Lattice Model of Disclinations in Liquid Crystals: Choice of Energy Function”,Macromolecules,27, 3239 (1994).

    Article  Google Scholar 

  • Baek, S. G., Magda, J. J., Larson, R. G. and Hudson, S. D., “Rheological Differences Among Liquid-Crystalline Polymers. II. Disappearance of Negative N1 in Densely Packed Lyotropes and Thermotropes”,J. Rheol.,38, 1473 (1994).

    Article  CAS  Google Scholar 

  • Bedford, S. E., Nicholson, T. M. and Windle, A. H., “A Supra-molecular Approach to the Modeling of Textures in Liquid Crystals”,Liq. Cryst.,10, 63 (1991).

    Article  Google Scholar 

  • Bird, R. B., Armstrong, R. C. and Hassager, O., “Dynamics of Polymeric Liquids. Volume 1 Fluid Mechanics”, 2nd Ed., John Weily & Sons, New York (1987).

    Google Scholar 

  • Chandrasekhar, S., “Liquid Crystals”, 2nd Ed., Cambridge University Press, Cambridge (1992).

    Google Scholar 

  • Chang, S. and Han, C. D., “A Thermotropic Main-Chain Random Copolyester Containing Flexible Spacers of Differing Lengths. 2. Rheological Behavior”,Macromolecules,30, 1656 (1997).

    Article  CAS  Google Scholar 

  • Chow, A. W. and Fuller, G. G., “Rheological Response of Rodlike Chains Subjected to Transient Shear Flow. 1. Model Calculations on the Effects of Polydispersity”,Macromolecules,18, 786 (1985).

    Article  CAS  Google Scholar 

  • Cocchini, F., Nobile, M. R. and Acierno, D., “Letter: About Negative First Normal Stress Differences in a Thermotropic Liquid Crystalline Polymer”,J. Rheol.,36, 1307 (1992).

    Article  CAS  Google Scholar 

  • Ding, J. and Yang, Y., “Brownian Dynamics Simulation of Rodlike Polymers under Shear Fflow”,Rheol. Acta,33, 405 (1994).

    Article  CAS  Google Scholar 

  • Doi, M., “Effect of Chain Flexibility on the Dynamics of Rodlike Polymers in the Entangled State”,J. Polym. Sci. Polym. Symp.,73, 93 (1985).

    Article  CAS  Google Scholar 

  • Doi, M., “Molecular Dynamics and Rheological Properties of Concentrated Solutions of Rodlike Polymers in Isotropic and Liquid Crystalline Phases”,J. Polym. Sci. Polym. Phys. Ed.,19, 229 (1981).

    Article  CAS  Google Scholar 

  • Donald, A. M. and Windle, A. H., “Liquid Crystalline Polymers”, Cambridge University Press, Cambridge (1992).

    Google Scholar 

  • Done, D. and Baird, D. G., “Solidification Behaviors and Recovery Kinetics of Liquid Crystalline Polymers”,Polym. Eng. Sci.,30, 989 (1990).

    Article  CAS  Google Scholar 

  • Driscoll, P., Hayase, S. and Masuda, T. “Viscoelastic Properties of a 60 mol% para-Hydroxybenzoic Acid/40 mol% Poly(ethylene terephthalate) Liquid Crystalline Copolyester. II: Effect of Shear History”,Polym. Eng. Sci.,34, 519 (1994).

    Article  CAS  Google Scholar 

  • De Gennes, P. G. and Prost, J., “The Physics of Liquid Crystals”, 2nd Ed., Clarendon Press, Oxford (1992).

    Google Scholar 

  • Gervat, L., Mackley, M. R., Nicholson, T. M. and Windle, A. H., “The Effect of Shear on Thermotropic Liquid Crystalline Polymers”,Phil. Trans. Roy. Soc. Lond.,A350, 1 (1995).

    Article  Google Scholar 

  • Gleeson, J. T., Larson, R. G., Mead, D. W., Kiss, G. and Cladis, P. E., “Image Analysis of Shear-induced Textures in Liquid-crystalline Polymers”,Liq. Cryst.,11, 341 (1992).

    Article  CAS  Google Scholar 

  • Guskey, S. M. and Winter, H. H., “Transient Shear Behaviors of a Thermotropic Liquid Crystalline Polymer in the Nematic State”,J. Rheol.,35, 1191 (1991).

    Article  CAS  Google Scholar 

  • Han, C. D. and Chang, S., “Note: On the First Normal Stress Difference of the Thermotropic Copolyester 73/27 HBA/HNA”,J. Rheol.,38, 241 (1994).

    Article  CAS  Google Scholar 

  • Han, W. H. and Rey, A. D., “Simulation and Validation of Temperature Effects on the Nematorheology of Aligning and Nonaligning Liquid Crystals”,J. Rheol.,39, 301 (1995).

    Article  CAS  Google Scholar 

  • Hanna, S. and Windle, A. H., “Geometric Limits to Order in Liquid Crystalline Random Copolymers”,Polymer,29, 207 (1988).

    Article  CAS  Google Scholar 

  • Hongladarom, K. and Burghardt, W. R., “Measurement of the Full Refractive Index Tensor in Sheared Liquid Crystalline Polymer Solutions”,Macromolecules,27, 483 (1994).

    Article  CAS  Google Scholar 

  • Kamath, V. M. and Mackley, M. R., “The Determination of Polymer Relaxation Moduli and Memory Functions using Integral Transforms”,J. Non-Newtonian Fluid Mech.,32, 119 (1989).

    Article  CAS  Google Scholar 

  • Kim, K. M. and Chung, I. J., “Structural Change of Polydomain in the Liquid Crystalline Polymers by Weak Shear Flow”,Korean J. Chem. Eng.,14 (1997).

  • Kim, K. M., Cho, H. and Chung, I.J., “Defect Density Evolution and Steady Rheological Behaviors of Liquid Crystalline Polymers”,J. Rheol.,38, 1271 (1994).

    Article  CAS  Google Scholar 

  • Kim, S. O., Kim, T. K. and Chung, I. J., “Synthesis and Rheological Investigation on Phase Behaviors of Semiflexible Type Amorphous Liquid Crystalline Poly(ester-imide)s”,Polymer,41, 4709 (2000).

    Article  CAS  Google Scholar 

  • Kim, S. S. and Han, C. D., “Effect of Shear History on the Steady Shear Flow Behavior of a Thermotropic Liquid-crystalline Polymer”,J. Polym. Sci. Part B: Polym. Phys.,32, 371 (1994).

    Article  CAS  Google Scholar 

  • Kim, S. S. and Han, C. D., “Effect of Thermal History on the Rheological Behavior of a Thermotropic Liquid-crystalline Polymer”,Macromolecules,26, 3176 (1993a).

    Article  CAS  Google Scholar 

  • Kim, S.S. and Han, C. D., “Transient Rheological Behavior of a Thermotropic Liquid Crystalline Polymer. I. The Start-up of Shear Flow”,J. Rheol.,37, 847 (1993b).

    Article  CAS  Google Scholar 

  • Kim, T. K., Kim, K. M. and Chung, I.J., “Effects of Monomeric Sequence Distribution on Physical Properties of Thermotropic Liquid Crystalline Copoly(ester-imide)s”,Polym. J.,29, 85 (1997a).

    Article  Google Scholar 

  • Kim, T. K., Kim, S. O. and Chung, I. J., “Synthesis and Characterization of Thermotropic Liquid Crystalline Copoly(ester-imide)s”,Polym. Adv. Technol.,8, 305 (1997).

    Article  CAS  Google Scholar 

  • Kimura, T. and Gray, D. G., “Annealing Method for Modeling Liquid Crystal Textures”,Macromolecules,26, 3455 (1993).

    Article  CAS  Google Scholar 

  • Kiss, G. and Porter, R. S., “Rheology of Concentrated Solutions of Poly(γ-benzyl-glutamate)”,J. Polym. Sci. Polym. Symp.,65, 193 (1978).

    CAS  Google Scholar 

  • Kleman, M., Liebert, L. and Strezelecki, L., “Preliminary Observations of Defects in a Polymeric Nematic Phase”,Polymer,24, 295 (1983).

    Article  CAS  Google Scholar 

  • Langelaan, H. C. and Gotsis, A. D., “The Relaxation of Shear and Normal Stresses of Nematic Liquid Crystalline Polymers in Squeezing and Shear Flows”,J. Rheol.,40, 107 (1996).

    Article  CAS  Google Scholar 

  • Larson, R. G. “Arrested Tumbling in Shearing Flows of Liquid Crystal Polymers”,Macromolecules,23, 3983 (1990).

    Article  CAS  Google Scholar 

  • Larson, R. G. and Doi, M., “Mesoscopic Domain Theory for Textured Liquid Crystalline Polymers”,J. Rheol.,35, 539 (1991).

    Article  CAS  Google Scholar 

  • Larson, R. G. and Mead, D. W., “Linear Viscoelasticity of Nematic Liquid Crystalline Polymers”,J. Rheol.,33, 185 (1989).

    Article  CAS  Google Scholar 

  • Larson, R. G. and Mead, D.W., “Toward A Quantitative Theory of the Rheology of Concentrated Solutions of Stiff Polymers”,J. Polym. Sci. Polym. Phys. Ed.,29, 1271 (1991).

    Article  CAS  Google Scholar 

  • Lee, S. D. and Meyer, R. B., “Crossover Behavior of the Elastic Coefficients and Viscosities of a Polymeric Nematic Liquid Crystal”,Phys. Rev. Lett.,61, 2217 (1988).

    Article  CAS  Google Scholar 

  • Lin, Y. G. and Winter, H. H., “Formation of a High Melting Crystals in a Thermotropic Aromatic Copolyester”,Macromolecules,21, 2439 (1989).

    Article  Google Scholar 

  • Marrucci, G. and Grizzuti, N., “The Effect of Polydispersity on Rotational Diffusivity and Shear Viscosity of Rodlike Polymers in Concentrated Solutions”,J. Polym. Sci. Polym. Lett. Ed.,21, 83 (1983).

    Article  CAS  Google Scholar 

  • Nakai, A., Wang, W., Hashimoto, T., Blumstein, A. and Maeda, Y., “Phase Separation Process and Self-organization of Textures in the Biphase Region of Thermotropic Liquid Crystalline Poly(4,4dioxy-2,2-dimethylazoxybenzene-dodecanedioyl). 1. A Study on the Athermal Conditions”,Macromolecules,27, 6963 (1994).

    Article  CAS  Google Scholar 

  • Picken, S. J., Moldenaers, P., Berghmans, S. and Mewis, J., “Experimental and Theoretical Analysis of Band Formation in Polymeric Liquid Crystals Upon Cessation of Flow”,Macromolecules,25, 4759 (1992)

    Article  CAS  Google Scholar 

  • Semenov, A. N., “Domain Formation in Liquid Crystals Under Oscillating Shear Flow”,J. Rheol.,37, 911 (1993).

    Article  CAS  Google Scholar 

  • Viola, G. G. and Baird, D. G., “Studies on the Transient Shear Flow Behavior of Liquid Crystalline Polymers”,J. Rheol.,30, 601 (1986).

    Article  CAS  Google Scholar 

  • Winter, H. H. and Wedler, W., “Note: About Measuring the First Normal Stress Difference in Shear Flow of a Thermotropic Copolyester”,J. Rheol.,37, 409 (1993).

    Article  CAS  Google Scholar 

  • Wissbrun, K. F., “Observations on the Melt Rheology of Thermotropic Aromatic Polyesters”,Brit. Polym. J.,12, 163 (1980).

    CAS  Google Scholar 

Download references

Author information

Authors and Affiliations

  1. Department of Chemical Engineering, Korea Advanced Institute of Science and Technology (KAIST), 373-1 Kusong, 305-701, Yusong, Taejon, Korea

    Hansol Cho, Mingzhe Xu, Sang Ouk Kim, Kwang Man Kim & In Jae Chung

Authors
  1. Hansol Cho
    View author publications

    You can also search for this author in PubMed Google Scholar

  2. Mingzhe Xu
    View author publications

    You can also search for this author in PubMed Google Scholar

  3. Sang Ouk Kim
    View author publications

    You can also search for this author in PubMed Google Scholar

  4. Kwang Man Kim
    View author publications

    You can also search for this author in PubMed Google Scholar

  5. In Jae Chung
    View author publications

    You can also search for this author in PubMed Google Scholar

Corresponding author

Correspondence to In Jae Chung.

Rights and permissions

Reprints and permissions

About this article

Cite this article

Cho, H., Xu, M., Kim, S.O. et al. Microstructural lattice simulation and transient rheological behavior of a flow-aligning liquid crystalline polymer under low shear rates. Korean J. Chem. Eng. 18, 46–53 (2001). https://doi.org/10.1007/BF02707197

Download citation

  • Received:

  • Accepted:

  • Issue Date:

  • DOI: https://doi.org/10.1007/BF02707197

Key words

Search

Navigation