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<h2> The properties of silk </h2> | <h2> The properties of silk </h2> | ||
| - | <p>The unique properties of silk are a result of its highly constant and repetitive amino-acid structure. The sequence of amino-acids determines what secondary structures will arise, and thus the final preferred protein conformation. The secondary structures may be beta sheets, beta-spirals, and beta-helices, of which the sheets realize the silk's amazing tensile strength, and the spirals and helices its elongation. | + | <p>The unique properties of silk are a result of its highly constant and repetitive amino-acid structure. The sequence of amino-acids determines what secondary structures will arise, and thus the final preferred protein conformation. The secondary structures may be beta sheets, beta-spirals, and beta-helices, of which the sheets realize the silk's amazing tensile strength, and the spirals and helices its elongation.</p> |
| - | </p> | + | <p>In the figure below a stress-strain diagram can be found (Frank K. Ko, et at. 2001) where Clavipus spider silk is compared to, Kevlar 29, normal silkworm silk, PET (polyethylene terephthalate), Nylon 6, and Merino wool. The stress-strain diagram relates the degree of deformation to the amount of energy absorbed. </p> |
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When used as clothing, silk has many beneficial properties. Its smooth, compact surface feels and looks nice, and it enables easy removal of dirt. It is a bad conductor of heat, making it cool in the summer and warm in the winter. Furthermore, it has a water absorption efficiency similar to that of wool, and is resistant to insects and mildew. | When used as clothing, silk has many beneficial properties. Its smooth, compact surface feels and looks nice, and it enables easy removal of dirt. It is a bad conductor of heat, making it cool in the summer and warm in the winter. Furthermore, it has a water absorption efficiency similar to that of wool, and is resistant to insects and mildew. | ||
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| + | <h3> References </h3> | ||
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| + | [1] Frank K. Ko, et al. (2001). "Engineering properties of spider silk". MRS Proceedings, vol. 702 | ||
| + | </p> | ||
<h1> </h1> | <h1> </h1> | ||
Revision as of 08:45, 8 June 2013
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Contents |
Background
The origin of silk
Ancient Chinese legend has it that a princess named Xi Linshi, who was having a relaxing afternoon under a Mulberry tree, first discovered silk 4500 years ago when a cocoon suddenly fell in her tee. After some time, Xi Linshi extracted a silk thread from her still steaming cup of thee, and unraveled the secret of silk along with its cocoon.
The knowledge that silk could be extracted from insect cocoons was closely guarded, and harsh conditions were set (the penalty of death) to anyone who was caught smuggling the eggs or cocoons. By such means, China realized a two thousand year monopoly of the silk industry, which was, according to yet another legend, put to an end when a Chinese princess smuggled moth eggs and mulberry seeds as a gift for her future husband. Subsequent to the princesses betrayal, the secret of silk was still kept secret from the west for another good thousand years or so, as it was only in the 12th century ACE that sericulture (the production of silk) began to develop.
Silk has thus inspired many legends and myths. Whether the stories are true or not, it is a fact that the discovery of silk has had world-wide impacts on culture, economy, development, and trade due to its much desired properties.
The properties of silk
The unique properties of silk are a result of its highly constant and repetitive amino-acid structure. The sequence of amino-acids determines what secondary structures will arise, and thus the final preferred protein conformation. The secondary structures may be beta sheets, beta-spirals, and beta-helices, of which the sheets realize the silk's amazing tensile strength, and the spirals and helices its elongation.
In the figure below a stress-strain diagram can be found (Frank K. Ko, et at. 2001) where Clavipus spider silk is compared to, Kevlar 29, normal silkworm silk, PET (polyethylene terephthalate), Nylon 6, and Merino wool. The stress-strain diagram relates the degree of deformation to the amount of energy absorbed.
When used as clothing, silk has many beneficial properties. Its smooth, compact surface feels and looks nice, and it enables easy removal of dirt. It is a bad conductor of heat, making it cool in the summer and warm in the winter. Furthermore, it has a water absorption efficiency similar to that of wool, and is resistant to insects and mildew.
A final general property of silk it that it can be integrated with the human body - it will not induce an immune response - potentially making it an ideal choice for many biomedical applications. Its compatibility extends to the gastrointestinal tract, that is, it is even safe to eat!
References
[1] Frank K. Ko, et al. (2001). "Engineering properties of spider silk". MRS Proceedings, vol. 702
