Nanotechnology Now

Our NanoNews Digest Sponsors

Heifer International

Wikipedia Affiliate Button

Home > Press > MIT: Nanocomposities yield strong, stretchy fibers

Abstract:
Creating artificial substances that are both stretchy and strong has long been an elusive engineering goal. Inspired by spider silk, a naturally occurring strong and stretchy substance, MIT researchers have now devised a way to produce a material that begins to mimic this combination of desirable properties.

MIT: Nanocomposities yield strong, stretchy fibers

Cambridge, MA | Posted on January 19th, 2007

Such materials, known as polymeric nanocomposites, could be used to strengthen and toughen packaging materials and develop tear-resistant fabrics or biomedical devices. Professor Gareth McKinley, graduate student Shawna Liff and postdoctoral researcher Nitin Kumar worked at MIT's Institute for Soldier Nanotechnologies (ISN) to develop a new method for effectively preparing these materials. The research appears in the January issue of Nature Materials.

Engineers are already able to create materials that are either very strong or very stretchy, but it has been difficult to achieve both qualities in the same material. In the last few years scientists have determined that the secret behind the combined strength and flexibility of spider silk lies in the arrangement of the nano-crystalline reinforcement of the silk while it is being produced.

"If you look closely at the structure of spider silk, it is filled with a lot of very small crystals," says McKinley, a professor of mechanical engineering. "It's highly reinforced."

The silk's strength and flexibility come from this nanoscale crystalline reinforcement and from the way these tiny crystals are oriented towards and strongly adhere to the stretchy protein that forms their surrounding polymeric matrix.

Liff, a Ph.D. student in mechanical engineering, and Kumar, a former MIT postdoctoral associate, teamed up to figure out how to begin to emulate this nano-reinforced structure in a synthetic polymer (A polymer or plastic consists of long chains composed of small repeating molecular units). Numerous earlier unsuccessful attempts, tackling the same issue, relied on heating and mixing molten plastics with reinforcing agents, but Liff and Kumar took a different approach: They focused on reinforcing solutions of a commercial polyurethane elastomer (a rubbery substance) with nanosized clay platelets.

They started with tiny clay discs, the smallest they could find (about 1 nanometer, or a billionth of a meter thick and 25 nanometers in diameter). The discs are naturally arranged in stacks like poker chips, but "when you put them in the right solvent, these 'nanosized poker chips' all come apart," said McKinley.

The researchers developed a process to embed these clay chips in the rubbery polymer-first dissolving them in water, then slowly exchanging water for a solvent that also dissolves polyurethane. They then dissolved the polymer in the new mixture, and finally removed the solvent. The end result is a "nanocomposite" of stiff clay particles dispersed throughout a stretchy matrix that is now stronger and tougher.

Importantly, the clay platelets are distributed randomly in the material, forming a structure much like the jumble that results when you try to stuff matches back into a matchbox after they have all spilled out.
Instead of a neatly packed arrangement, the process results in a very disorderly "jammed" structure, according to McKinley. Consequently the nanocomposite material is reinforced in every direction and the material exhibits very little distortion even when heated to temperatures above 150 degrees Celsius.

In a Nature Materials commentary that accompanied the research paper, Evangelos Manias, professor of materials science and engineering at the University of Pennsylvania, suggests that "molecular composites" such as those developed by the MIT group are especially suitable for new lightweight membranes and gas barriers, because the hard clay structure provides extra mechanical support and prevents degradation of the material even at high temperatures. One possible use for such barriers is in fuel cells.

The U.S. military is interested in such materials for use in possible applications such as tear-resistant films or other body-armor components. The military is also interested in thinner, stronger packaging films for soldiers' MREs (meals ready to eat) to replace the thick and bulky packaging now used.

Fabric companies have also expressed interest in the new materials, which can be used to make fibers similar to stretchy compounds such as nylon or Lycra. The new approach to making nanocomposites can also be applied to biocompatible polymers and could be used to make stents and other biomedical devices, McKinley said.

The research was funded by the U.S. Army through MIT's Institute for Soldier Nanotechnologies and by the National Science Foundation. McKinley's team was assisted by technical staff at the ISN, including research engineer Steven Kooi, who helped prepare special samples for transmission electron microscopy.

####

About Massachusetts Institute of Technology
The mission of MIT is to advance knowledge and educate students in science, technology, and other areas of scholarship that will best serve the nation and the world in the 21st century.

The Institute is committed to generating, disseminating, and preserving knowledge, and to working with others to bring this knowledge to bear on the world's great challenges. MIT is dedicated to providing its students with an education that combines rigorous academic study and the excitement of discovery with the support and intellectual stimulation of a diverse campus community. We seek to develop in each member of the MIT community the ability and passion to work wisely, creatively, and effectively for the betterment of humankind.

For more information, please click here

Contacts:
Elizabeth A. Thomson, MIT News Office
617-258-5402

Copyright © Massachusetts Institute of Technology

If you have a comment, please Contact us.

Issuers of news releases, not 7th Wave, Inc. or Nanotechnology Now, are solely responsible for the accuracy of the content.

Bookmark:
Delicious Digg Newsvine Google Yahoo Reddit Magnoliacom Furl Facebook

Related News Press

Nanomedicine

Arrowhead Presents ARC-520 and ARC-521 Clinical Data at The International Liver Congress(TM) April 20th, 2017

Nano-SPEARs gently measure electrical signals in small animals: Rice University's tiny needles simplify data gathering to probe diseases, test drugs April 17th, 2017

Nanotubes that build themselves April 14th, 2017

Emergency Use Authorization for Gene-RADAR® Zika Virus Test: FDA Authorization for the Gene-RADAR® Zika Virus Test on the XPRIZE-Winning Gene-RADAR® Platform April 14th, 2017

Discoveries

Two-dimensional melting of hard spheres experimentally unravelled after 60 years: First definitive experimental evidence of two-dimensional melting of hard spheres April 21st, 2017

Wood filter removes toxic dye from water April 21st, 2017

Rice crew revved for Nanocar Race: Nanocar creator James Tour and team take on international competition with single-molecule marvel April 20th, 2017

Better living through pressure: Functional nanomaterials made easy April 19th, 2017

Materials/Metamaterials

Two-dimensional melting of hard spheres experimentally unravelled after 60 years: First definitive experimental evidence of two-dimensional melting of hard spheres April 21st, 2017

National Conference on Nanomaterials, (NCN-2017) April 21st, 2017

Forge Nano 2017: 1st Quarter Media Update April 20th, 2017

Making Batteries From Waste Glass Bottles: UCR researchers are turning glass bottles into high performance lithium-ion batteries for electric vehicles and personal electronics April 19th, 2017

Announcements

Two-dimensional melting of hard spheres experimentally unravelled after 60 years: First definitive experimental evidence of two-dimensional melting of hard spheres April 21st, 2017

National Conference on Nanomaterials, (NCN-2017) April 21st, 2017

NanoMONITOR shares its latest developments concerning the NanoMONITOR Software and the Monitoring stations April 21st, 2017

Nanomechanics, Inc. Unveils New Product at ICMCTF Show April 25th: Nanoindentation experts will launch the new Gemini that measures the interaction of two objects that are sliding across each other – not merely making contact April 21st, 2017

Military

Nano-SPEARs gently measure electrical signals in small animals: Rice University's tiny needles simplify data gathering to probe diseases, test drugs April 17th, 2017

New technology could offer cheaper, faster food testing: Specialized droplets interact with bacteria and can be analyzed using a smartphone April 7th, 2017

Teri Odom and Richard Van Duyne Honored by Department of Defense: Each will receive $3 million over five years to conduct high-risk, high-payoff research March 31st, 2017

NIST physicists show ion pairs perform enhanced 'spooky action' March 30th, 2017

Textiles/Clothing

New ultrafast flexible and transparent memory devices could herald new era of electronics April 1st, 2017

'Back to the Future' inspires solar nanotech-powered clothing November 15th, 2016

Engineers develop new magnetic ink to print self-healing devices that heal in record time November 7th, 2016

Stretchy supercapacitors power wearable electronics August 25th, 2016

Fuel Cells

Promising results obtained with a new electrocatalyst that reduces the need for platinum: Researchers from Aalto University have succeeded in manufacturing electrocatalysts used for storing electric energy with one-hundredth of the amount of platinum that is usually needed March 24th, 2017

Scientists boost catalytic activity for key chemical reaction in fuel cells: New platinum-based catalysts with tensile surface strain could improve fuel cell efficiency December 19th, 2016

It's basic: Alternative fuel cell technology reduces cost: Study sets performance targets for metal-free fuel cell membrane December 13th, 2016

Keeping electric car design on the right road: A closer look at the life-cycle impacts of lithium-ion batteries and proton exchange membrane fuel cells December 9th, 2016

NanoNews-Digest
The latest news from around the world, FREE



  Premium Products
NanoNews-Custom
Only the news you want to read!
 Learn More
NanoTech-Transfer
University Technology Transfer & Patents
 Learn More
NanoStrategies
Full-service, expert consulting
 Learn More











ASP
Nanotechnology Now Featured Books




NNN

The Hunger Project