“Spider silk has a unique combination of mechanical strength and elasticity that make it one of the toughest materials we know,” said Jeffery Yarger, a professor in ASU’s Department of Chemistry and Biochemistry and lead researcher of the study. “This work represents the most complete understanding we have of the underlying mechanical properties of spider silks.”
Female Nephila clavipes on her web. The web was characterized by the ASU team using Brillouin spectroscopy to directly and non-invasively determine the mechanical properties.
Spider silk is an exceptional biological polymer, related to collagen (the stuff of skin and bones) but much more complex in its structure. The ASU team of chemists is studying its molecular structure in an effort to produce materials ranging from bulletproof vests to artificial tendons.
The extensive array of elastic and mechanical properties of spider silks in situ, obtained by the ASU team, is the first of its kind and will greatly facilitate future modeling efforts aimed at understanding the interplay of the mechanical properties and the molecular structure of silk used to produce spider webs.
The team published their results in today’s advanced online issue of Nature materials and their paper is titled “Non-invasive determination of the complete elastic moduli of spider silks.”
“This information should help provide a blueprint for structural engineering of an abundant array of bio-inspired materials, such as precise materials engineering of synthetic fibers to create stronger, stretchier and more elastic materials,” explained Yarger.
Other members of Yarger’s team, in ASU’s College of Liberal Arts and Sciences, included Kristie Koski, at the time a postdoctoral researcher and currently a postdoctoral fellow at Stanford University, and ASU undergraduate students Paul Akhenblit and Keri McKiernan.
The Brillouin light scattering technique used an extremely low power laser, less than 3.5 milliwatts, which is significantly less than the average laser pointer. Recording what happened to this laser beam as it passed through the intact spider webs enabled the researchers to spatially map the elastic stiffnesses of each web without deforming or disrupting it. This non-invasive, non-contact measurement produced findings showing variations among discrete fibers, junctions and glue spots.
Four different types of spider webs were studied. They included Nephila clavipes (pictured), A. aurantia (“gilded silver face”-common to the contiguous United States), L. Hesperus, the western black widow and P. viridans, the green lynx spider, the only spider included that does not build a web for catching prey but has major silk elastic properties similar to those of the other species studied.
The group also investigated one of the most studied aspects of orb-weaving dragline spider silk, namely supercontraction, a property unique to silk. Spider silk takes up water when exposed to high humidity. Absorbed water leads to shrinkage in an unrestrained fiber up to 50 percent shrinkage with 100 percent humidity in N. clavipes silk.
Their results are consistent with the hypothesis that supercontraction helps the spider tailor the properties of the silk during spinning. This type of behavior, specifically adjusting mechanical properties by simply adjusting water content, is inspirational from a bio-inspired mechanical structure perspective.
“This study is unique in that we can extract all the elastic properties of spider silk that cannot and have not been measured with conventional testing,” concluded Yarger.
The Department of Defense and the National Science Foundation supported this research.Jenny Green, email@example.com
Jenny Green | Newswise
Speech dynamics are coded in the left motor cortex
31.03.2015 | Universitätsmedizin Göttingen - Georg-August-Universität
Discovery of two new species of primitive fishes discovered
31.03.2015 | Universität Zürich
In an experiment at the Department of Energy's SLAC National Accelerator Laboratory, scientists precisely measured the temperature and structure of aluminum as...
The IPH presents a solution at HANNOVER MESSE 2015 to make ship traffic more reliable while decreasing the maintenance costs at the same time. In cooperation with project partners, the research institute from Hannover, Germany, has developed a sensor system which continuously monitors the condition of the marine gearbox, thus preventing breakdowns. Special feature: the monitoring system works wirelessly and energy-autonomously. The required electrical power is generated where it is needed – directly at the sensor.
As well as cars need to be certified regularly (in Germany by the TÜV – Technical Inspection Association), ships need to be inspected – if the powertrain stops...
When an earthquake hits, the faster first responders can get to an impacted area, the more likely infrastructure--and lives--can be saved.
The Atlantic overturning is one of Earth’s most important heat transport systems, pumping warm water northwards and cold water southwards. Also known as the Gulf Stream system, it is responsible for the mild climate in northwestern Europe.
Scientists now found evidence for a slowdown of the overturning – multiple lines of observation suggest that in recent decades, the current system has been...
Because they are regularly subjected to heavy vehicle traffic, emissions, moisture and salt, above- and underground parking garages, as well as bridges, frequently experience large areas of corrosion. Most inspection systems to date have only been capable of inspecting smaller surface areas.
From April 13 to April 17 at the Hannover Messe (hall 2, exhibit booth C16), engineers from the Fraunhofer Institute for Nondestructive Testing IZFP will be...
25.03.2015 | Event News
19.03.2015 | Event News
17.03.2015 | Event News
31.03.2015 | Life Sciences
31.03.2015 | Life Sciences
31.03.2015 | Life Sciences