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Liquid Crystalline Characteristics of Natural Silk Secretions

Published online by Cambridge University Press:  15 February 2011

Keven Kerkam ,
David Kaplan ,
Stephen Lombardi  and
Christopher Viney
Keven Kerkam
Affiliation:
Department of Materials Science and Engineering FB-10, and the Advanced Materials Technology Program, University of Washington, Seattle, WA 98195
David Kaplan
Affiliation:
US Army Research, Development and Engineering Center, Natick, MA 01760
Stephen Lombardi
Affiliation:
US Army Research, Development and Engineering Center, Natick, MA 01760
Christopher Viney
Affiliation:
Department of Materials Science and Engineering FB-10, and the Advanced Materials Technology Program, University of Washington, Seattle, WA 98195
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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.

Type
Research Article
Information
MRS Online Proceedings Library (OPL) , Volume 218: Symposium V – Materials Synthesis Based on Biological Processes , 1990 , 239
Copyright
Copyright © Materials Research Society 1991

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