Wednesday, January 20, 2016

How shells get their strength

This is an excerpt from an article published on the Pacific Northwest National Laboratory's website. You can see the original post here.

 Image result for chalkImage result for oyster shell

Both are calium carbonate, but one is hard, the other is soft. Why?

How seashells get their strength

Study shows how calcium carbonate forms composites to make strong materials such as in shells and pearls
January 08, 2016

RICHLAND, Wash. – Seashells and lobster claws are hard to break, but chalk is soft enough to draw on sidewalks. Though all three are made of calcium carbonate crystals, the hard materials include clumps of soft biological matter that make them much stronger. A study today in Nature Communications reveals how soft clumps get into crystals and endow them with remarkable strength.

The results show that such clumps become incorporated via chemical interactions with atoms in the crystals, an unexpected mechanism based on previous understanding. By providing insight into the formation of natural minerals that are a composite of both soft and hard components, the work will help scientists develop new materials for a sustainable energy future, based on this principle.

"This work helps us to sort out how rather weak crystals can form composite materials with remarkable mechanical properties," said materials scientist Jim De Yoreo of the Department of Energy's Pacific Northwest National Laboratory. "It also provides us with ideas for trapping carbon dioxide in useful materials to deal with the excess greenhouse gases we're putting in the atmosphere, or for incorporating light-responsive nanoparticles into highly ordered crystalline matrices for solar energy applications."

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