Abstract
We have used transmitted polarized light microscopy to examine the fluid contents of silk glands taken from Bombyx mori silkworms and Nephila clavipes orb-weaving spiders. In the absence of shear, the secretions are optically isotropic. As the concentration is allowed to increase by evaporation, microstructures typical of the nematic liquid crystalline state are observed. Thus it appears that naturally spun silk becomes liquid crystalline en route to solidifying into fiber - which is advantageous to introducing and retaining global molecular alignment. This will facilitate the formation of strong, stiff fibers without the need for a significant post-spinning draw. We have also found that natural silk does not exhibit the defects in molecular alignment that are typical of synthetic polymer fibers spun from liquid crystalline solutions or melts.
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References
J.M. Gosline, M.E. DeMont and M.W. Denny, Endeavour 10, 37 (1986).
J.C. Zemiin, Technical Report 69-29-CM (AD 684333), U.S. Army Natick Laboratories, Natick MA, 1968.
F.W. Billmeyer, Textbook of Polymer Science (John Wiley, New York, 1984), pg. 502.
Liquid-Crystalline Polymers, edited by R.A. Weiss and C.K. Ober (American Chemical Society Symposium Series 435, Washington DC, 1990).
F. Lucas and K.M. Rudall in Comprehensive Biochemistry, edited by M. Florkin and E.H. Stotz (Elsevier, Amsterdam, 1968) 26B, Ch.7.
J. Magoshi, Y. Magoshi and S. Nakamura, J. Appl. Polym. Sci.: Appl. Polym. Symp. 41, 187 (1985).
J. Magoshi, Y. Magoshi and S. Nakamura, Polym. Commun. 26, 60 (1985).
G. Li and T. Yu, Makromol. Chem. Rapid Commun. 10, 387 (1989).
E. lizuka, J. Appl. Polym. Sci.: Appl. Polym. Symp. 41., 173 (1985).
M.G. Dobb, and J.E. McIntyre, Adv. in Polym. Sci. 60/61, 61 (1984).
A. Elliot and E.J. Ambrose, Discuss. Farad. Soc. 9, 246 (1950).
J.C. Cokendolpher and J.D. Brown, Ent. News 96, 114 (1985).
D. Demus and L. Richter, Textures of Liquid Crystals (Verlag Chemie, Weinheim, 1978).
G.W. Gray and J.W. Goodby, Smectic Liquid Crystals: Textures and Structures (Leonard Hill, Glasgow, 1984), pg. 58.
P.G. de Gennes, The Physics of Liquid Crystals (Oxford University Press, Oxford, 1979), ch.4.
F.C. Frank, Discuss. Farad. Soc. 25, 19 (1958).
C.M. Dannels, C. Viney, R.J. Twieg and M.Y. Chang, Mol. Cryst. Liq. Cryst., in press (1990).
A.M. Donald, C. Viney and A.H. Windle, Polymer 24, 155 (1983).
E. Marsano, L. Carpaneto and A. Ciferri, Mol. Cryst. Liq. Cryst. 158B, 267 (1988).
F. Fried and P. Sixou, Mol. Cryst. Liq. Cryst. 153B, 163 (1988).
B. Ernst, and P. Navard, Macromolecules 22, 1419 (1989).
C. Viney, A.M. Donald and A.H. Windle, Polymer 26, 870 (1985).
M.G. Dobb, D.J. Johnson and B.P. Saville, J. Polym. Sci.: Polym. Symp. 58, 237 (1977).
E.J. Roche, S.R. Allen, C.R. Fincher and C. Paulson, Mol. Cryst. Liq. Cryst. 153, 547 (1987).
W.S. Putnam and C. Viney, presented at the 13th International Liquid Crystal Conference, Vancouver, BC, 1990; submitted to Mol. Cryst. Liq. Cryst.
W.A. Shear, J.M. Palmer, J.A. Coddington and P.M. Bonamo, Science 246, 479 (1989).
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Kerkam, K., Kaplan, D., Lombardi, S. et al. Liquid Crystalline Characteristics of Natural Silk Secretions. MRS Online Proceedings Library 218, 239–244 (1990). https://doi.org/10.1557/PROC-218-239
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DOI: https://doi.org/10.1557/PROC-218-239