Nanotechnology Now

Our NanoNews Digest Sponsors





Heifer International

Wikipedia Affiliate Button


android tablet pc

Home > Press > Conch shell gives nano insights into composite materials

Abstract:
Writing in the International Journal of Materials Engineering Innovation, researchers at the University of Cambridge use the example of the conch shell as illustration of toughness-by-architecture in the quest for new synthetic materials for engineering, construction and aerospace applications.

The conch shell, symbol of juvenile democratic power on a desert island in William Golding's Lord of the Flies, also harbours a secret power of its own. The shells of sea snails are composed of about 95% calcium carbonate, the same material as crumbly chalk, yet they are a thousand times tougher. The other 5% is mainly organic matter. Writing in the International Journal of Materials Engineering Innovation, researchers at the University of Cambridge use the example of the conch shell as illustration of toughness-by-architecture in the quest for new synthetic materials for engineering, construction and aerospace applications.

Conch shell gives nano insights into composite materials

Cambridge, UK | Posted on March 23rd, 2011

David Williamson and Bill Proud review how these organisms build such tough shells from such a seemingly weak substance. They discover that the key to conch strength lies in the small size of the calcium carbonate crystals from which it is formed by the sea snail. The crystals are below a threshold size known as the Griffith flaw size, any bigger and the crystals would be large enough for cracks to propagate through them under stress, the team explains. This makes the shells tough enough to cope, to some extent, with the crushing jaws of predatory turtles and the vice-like grip of crab claws. Weight for weight the shells are as tough as mild steel.

In the early twentieth century, engineers were preoccupied with the premature failure of materials used in shipping and railways. Concepts such as stress magnification and the propagation of tiny cracks that grow to form big cracks were beginning to be understood. Civil engineer Charles Edward Inglis Inglis devised a mathematical equation to help explain the process. And, in 1920, Alan Arnold Griffith built on the Inglis work to explain for the first time that the reason materials in the real world are not as strong as theoretical calculations would suggest is that the presence of tiny flaws magnify the applied stress in a manner according to the Inglis analysis leading to premature failure.

"Griffith pointed out that the effective strength of technical materials might be increased many tens of times if these flaws could be eliminated," explain Williamson and Proud. Little was known at the time of biomaterials and how their properties might one day copied to create biomimetic materials of much greater strength than their industrial counterparts. Griffith's work has now been used to improve our understanding of conch shells and other biomaterials to allow scientists to produce novel composite biomimetic materials. Research in this area has seen almost exponential growth in the last decade.

The team explains that in the archetypal conch shell material, the queen conch (Strombus gigas) uses a crossed layered, or lamellar, structure. At the smallest length scale the shell is made from tiny crystals of calcium carbonate in the so-called orthorhombic polymorphic form of aragonite. Each single crystal is a mere 60 to 130 nanometres thick and about 100 to 380 nanometres across, although they can be several micrometres long. A nanometre is a billionth of a metre; a micrometre is a thousand times bigger, a millionth of a metre. These dimensions, the Cambridge team explains are below the critical flaw size described by Griffith almost a century ago.

To make a biomimetic material, researchers might first adopt the small crystal size for their composites as well as the crossed layered structure of the conch shell. However, to be truly biomimetic, such materials will also have to incorporate another critical feature of the living material: the ability to self-heal. Attacked by a hungry turtle the shell of a queen conch might be strong enough to deter the predator, but damage will occur, but living tissue can carry out repairs. Materials scientists have discovered that certain polymers can be heat treated so that they undergo self-healing, extended research might allow crystalline composites that mimic conch shell to be made that have the same property.

The team concludes that, it is important to treat these biomaterials as sources of inspiration, rather than prototypes to be replicated in exquisite detail. After all, if nature had access to a modern, high-tech material like the extremely tough ceramic titanium boride used in aluminium smelting equipment and electrical discharge machining, would seashells look the same as they do now?

####

For more information, please click here

Contacts:
David Williamson


Albert Ang
+ 44 1234 240519

Copyright © AlphaGalileo

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

News and information

University of Tehran Researchers Invent Non-Enzyme Sensor to Detect Blood Sugar April 23rd, 2014

Gold nanoparticles help target, quantify breast cancer gene segments in a living cell April 23rd, 2014

Study finds long-term survival of human neural stem cells transplanted into primate brain April 23rd, 2014

High-Performance, Low-Cost Ultracapacitors Built with Graphene and Carbon Nanotubes: Future devices based on technology could bridge gap between batteries and conventional capacitors in portable electronics and hybrid electric vehicles April 23rd, 2014

Discoveries

University of Tehran Researchers Invent Non-Enzyme Sensor to Detect Blood Sugar April 23rd, 2014

Gold nanoparticles help target, quantify breast cancer gene segments in a living cell April 23rd, 2014

Atomic switcheroo explains origins of thin-film solar cell mystery April 23rd, 2014

Characterizing inkjet inks: Malvern Instruments presents new rheological research April 23rd, 2014

Materials/Metamaterials

Guo Lab Shows Potential of RNA as Heat-resistant Polymer Material for Nanoarchitectures April 23rd, 2014

Nanomaterial Outsmarts Ions April 22nd, 2014

Thinnest feasible membrane produced April 17th, 2014

INSCX™ exchange to present Exchange trade reporting mechanism for engineered nanomaterials (NMs) to UK regulation agencies, insurers and upstream/downstream users April 17th, 2014

Announcements

Characterizing inkjet inks: Malvern Instruments presents new rheological research April 23rd, 2014

NanoSafe, Inc. announces the addition of the Labconco Protector® Glove Box to its NanoSafe Tested™ registry April 23rd, 2014

Study finds long-term survival of human neural stem cells transplanted into primate brain April 23rd, 2014

High-Performance, Low-Cost Ultracapacitors Built with Graphene and Carbon Nanotubes: Future devices based on technology could bridge gap between batteries and conventional capacitors in portable electronics and hybrid electric vehicles April 23rd, 2014

Aerospace/Space

National Space Society Congratulates SpaceX on the Success of CRS-3 and the First Flight of the Falcon 9R April 22nd, 2014

Tiny particles could help verify goods: Chemical engineers hope smartphone-readable microparticles could crack down on counterfeiting April 15th, 2014

NASA Engineers Prepare Game Changing Cryotank for Testing April 9th, 2014

Space Industry Leaders Countdown To Space Tech Expo 2014 – Opening Next Week: Space Tech Expo and Conference 2014 opens its doors at the Long Beach Convention Center, Long Beach April 1 – 3 March 30th, 2014

Construction

Scientists Produce Self-Cleaning Coatings on Glass Substrate March 17th, 2014

Iran Applying Nanotechnology in Growing Number of Industries March 10th, 2014

Colored diamonds are a superconductor’s best friend March 6th, 2014

Iranian, Spanish Scientists Investigate Thermal Stability of Nanostructured Bainitic Steel February 26th, 2014

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







© Copyright 1999-2014 7th Wave, Inc. All Rights Reserved PRIVACY POLICY :: CONTACT US :: STATS :: SITE MAP :: ADVERTISE