Abstract
The rheology of a side chain liquid crystalline polymer (SLCP) with a polysiloxane backbone was investigated. The dynamic shear moduli of the SLCP in a smectic phase did not show the normal terminal behavior as the homogenous polymeric melts did, and instead, they tended to level off in the low frequency terminal zone. Time–temperature superposition failed for both dynamic moduli in the low frequency terminal zone and the departure from the superposition became more evident in the vicinity of smectic/isotropic transition. The plateau-like moduli in the terminal zone indicated the layer structure of the smectic phase. The steady shear viscosities of the smectic phase exhibited a shear thinning behavior over the shear rates investigated. The shear thinning was lost at low shear rates when the temperature passed the smectic/biphasic border. The shear viscosity and the dynamic moduli showed a divergence in the neighborhood of the smectic/isotropic temperature. The activation energies of the shear viscosity and the moduli were smaller than that of the SLCP with polymethacrylate backbone. The rheological behavior of the SLCP at low frequencies and low shear rates was dominated by the smectogen.
Similar content being viewed by others
References
S. F. Rubin, R. M. Kannan and J. A. Kornfield, Macromolecules, 28, 3521 (1995).
S. D. Hudson, A. J. Lovinger, R. G. Larson, D. D. Davis, R. O. Garay and K. Fujishiro, Macromolecules, 26, 5643 (1993).
W. J. Zhou, J. A. Kornfield, V. M. Ugaz, W. R. Burghardt, D. R. Link and N. A. Clark, Macromolecules, 32, 5581 (1999).
I. Quijada-Garrido, H. Siebert, C. Friedrich and C. Schmidt, Macromolecules, 33, 3844 (2000).
D. F. Gu, A. M. Jamieson and S. Q. Wang, J. Rheol., 37, 985 (1993).
R. Zentel and J. Wu, Makromol. Chem., 187, 1727 (1986).
R. M. Kannan, J. A. Kornfield, N. Schwenk and C. Boeffel, Adv. Mater., 6(3), 214 (1994).
R. M. Kannan, S. F. Rubin, J. A. Kornfield and C. Boeffel, J. Rheol., 38, 1609 (1994).
D. J. Alt, S. D. Hudson, R. O. Garay and K. Fujishiro, Macromolecules, 28, 1575 (1995).
D. A. Grabowski and C. Schmidt, Macromolecules, 27, 2632 (1994).
J. Berghausen, J. Fuchs and W. Richtering, Macromolecules, 30, 7754 (1997).
R. M. Kannan, J. A. Kornfield, N. Schwenk and C. Boeffel, Macromolecules, 26, 2050 (1993).
F. Fabre and M. Veyssie, Mol. Cryst. Liq. Cryst. Lett., 4, 99 (1987).
R. H. Colby, J. R. Gillmor, G. Galli, M. Laus, C. K. Ober and E. Hall, Liquid Crystals, 13(2), 233 (1993).
A. Wewerka, G. Floudas, T. Pakula and F. Stelzer, Macromolecules, 34, 8129 (2001).
K. I. Tozaki, M. Kimura and S. Itou, J. Appl. Phys. (Japan), 33, 6633 (1994).
R. Zentel and M. Benalia, Makromol. Chem., 188, 665 (1987).
S. Bhattacharysa and S. V. Letcher, Phys. Rev. Lett., 44(6), 414 (1980).
P. A. Gemmel, G. W. Gray and D. Lacey, Mol. Cryst. Liq. Cryst., 122, 205 (1985).
P. Fabre, C. Casagrande and M. Veyssie, Phys. Rev. Lett., 53(10), 993 (1984).
H. Finkelmann and G. Rehage, Makromol. Chem. Rapid Commun., 3, 859 (1982).
H. Finkelmann, Phil. Trans. Roy. Soc. London A 309, 105 (1983).
H. Ringsdorf and A. Schneller, Makromol. Chem. Rapid Commun., 3, 557 (1982).
V. Percec and C. S. Hsu, Polymer Bull., 23, 463 (1990).
E. Akiyama, M. Ohtomo, Y. Nagase and N. Koide, Macromol. Chem. Phys., 196, 3391 (1995).
D. Taton, A. Le Borgne, N. Farina and C. Neol, Macromol. Chem. Phys., 196, 2941 (1995).
J. B. Reesink, S. J. Picken, A. J. Witteveen and W. J. Mijs, Macromol. Chem. Phys., 197, 1031 (1996).
W. Hawthorne, Ph.D. Thesis, University of York, UK, 1986.
P. Panizza, P. Archambault and D. Roux, J. Phys. II (France), 5, 303 (1995).
K. F. Wissbrun, J. Rheol., 25, 619 (1985).
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Yang, IK., Chang, S.H. The Smectic Rheology of a Polysiloxane Side Chain Liquid Crystalline Polymer. Journal of Polymer Research 9, 163–168 (2002). https://doi.org/10.1023/A:1021335507404
Issue Date:
DOI: https://doi.org/10.1023/A:1021335507404