Mechanical testing of spider silk - TU Wien · Biomacromolecules 1: 622-626. • Vollrath F.,...
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Mechanical testing of spider silk Bo Madsen Materials Research Division Risø National Laboratory for Sustainable Energy Technical University of Denmark Denmark COST Action FP0802 – Workshop on single fiber testing and modeling – Stockholm, Sweden, 4-5 Nov 2009
Transcript of Mechanical testing of spider silk - TU Wien · Biomacromolecules 1: 622-626. • Vollrath F.,...
Mechanical testing of spider silk
Bo Madsen
Materials Research DivisionRisø National Laboratory for Sustainable Energy
Technical University of DenmarkDenmark
COST Action FP0802 – Workshop on single fiber testing and modeling – Stockholm, Sweden, 4-5 Nov 2009
Typical properties of spider silk (Nephila edulis, major ampullate silk):Diameter: 3 μmInitial modulus: 8 GPaYield stress: 150 MPaBreaking stress: 1200 MPa Breaking strain: 0.40Breaking energy: 200 MJ/m3
Fixation of spider
Experimental procedure for tensile testing of spider silk
Sampling of silk from spider
Experimental procedure for tensile testing of spider silk
Sampling of silk from take-up spool
Experimental procedure for tensile testing of spider silk
Mounting of silk on tensile testing instrument
Experimental procedure for tensile testing of spider silk
Measurement of load-elongation behaviour of silk
Control of motor
LabView programson computer
Recording of data
Experimental procedure for tensile testing of spider silk
Data sampling panel
Motor setting panel
Instrument calibration panel
Data analysis panel
Measurement of load-elongation behaviour of silk
Experimental procedure for tensile testing of spider silk
Measurement of silk diameter
5 μm
Experimental procedure for tensile testing of spider silk
Video showing the experimental procedure
Experimental procedure for tensile testing of spider silk
Assessment of experimental procedure
Effect of glue type
Effect of stretching of silk thread
Assessment of experimental procedure
Diameter variation and roundness of silk
o Normal silk thread• Twisted silk thread
Assessment of experimental procedure
Variation in mechanical properties
Assessment of experimental procedure
Results
Difference in mechanical properties of silk from different spider species
1: Pisauridae2: Cyrtophora citricola3: Latrodectus mactans
4: Nephila edulis5: Araneus diadematus
Results
Effect of reeling speed
0.01 0.1 1 10 100 1000
Reeling speed (mm/s)
For “normal” reeling speedsbetween 0.01 and 20 mm/s:
-Thread diameter is decreased
- Breaking stress is increased
- Breaking strain is decreased
- Breaking energy is unchanged
Results
Effect of CO2 anesthesia
Silking time (s)
--- Control, no CO2
• CO2 between 120-210 so CO2 between 120-540 s
Results
Effect of CO2 anesthesia
Results
Effect of CO2 anesthesia
A: Before CO2 exposure
B: “Thinning” response
C: “Fibrillation” response after short time of CO2 exposure
D: “Fibrillation” response after long time of CO2 exposure
E: Example of sudden change in diameter
5 μm
5 μm
Current research on spider silk
Oxford Silk Group: http://users.ox.ac.uk/~abrg/spider_site/
References
• Madsen B. (1999). Mechanical properties of spider silk. Master thesis. Department of Zoology, University of Aarhus, Denmark.
• Madsen B., Shao Z.Z. and Vollrath F. (1999). Variability in themechanical properties of spider silks on three levels: interspecific, intraspecific and intraindividual. International Journal of Biological Macromolecules. 24: 301-306.
• Madsen B. and Vollrath F. (2000). Mechanics and morphology of silk drawn from anaesthetized spiders. Naturwissenschaften 87: 148-153.
• Riekel C., Madsen B., Knight D. and Vollrath F. (2000). X-ray diffraction on spider silk during controlled extrusion under a synchroton radiation X-ray beam. Biomacromolecules 1: 622-626.
• Vollrath F., Madsen B. and Shao Z.Z. (2001). The effect of spinning conditions on the mechanics of a spider’s dragline silk. The Royal Society, Proceedings in Biology. 268: 2339-2346.
