DailyDirt: The Strongest Natural Materials

from the urls-we-dig-up dept

Mother Nature is actually really good at making some impressively strong and tough materials. Kevlar and steel are pretty strong and useful, but there are a few natural materials that are stronger. Spider silk has been a synthetic target for decades, but being able to create just the spider silk protein isn't enough to make super strong fibers. Spiders actually produce different kinds of silk for different purposes with different mechanical properties, and the process of spinning spider silk isn't easy to duplicate without using spiders. If we're going to use less "plastic" in the future, we might need to figure out how to re-create some unique natural materials.

• The strongest natural material was previously thought to be spider silk, but the teeth of a type of mollusk (a limpet) is apparently stronger -- with a very high tensile strength that exceeds spider silk and Kevlar. Limpet teeth consist of protein packed with nanofibers of a mineral called goethite, and this composite material has a unique ability to maintain its strength regardless of its size -- usually larger structures tend to break more easily than smaller ones because they contain more flaws. [url]
• Tough seashells and corals are made of calcium carbonate, and it's been a mystery how this material forms -- but a piece of the puzzle has been found. Calcium carbonate can take the form of calcite or aragonite (and usually crystallizes into aragonite in seawater), but when the concentration of magnesium is reduced or eliminated, only calcite will form. If researchers can generalize the ability to predict crystal structure formation, it could have practical applications for a variety of material science problems. [url]
• Spider silk is often cited as being "stronger than steel" with possible applications for bulletproof vests or other amazing things. The problem is actually making spider silk on a large scale -- which means making the silk without growing a massive number of spiders. Various methods have been tried, such as using genetically modified bacteria, goats, silkworms, and alfalfa to produce strong silk fibers, but so far, we haven't quite been able to reproduce desirable spider silk fibers without using spiders. (There is at least one commercial use of spider silk, but it's used as a powder, not a fiber, for cosmetics.) [url]

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Filed Under: bioinspiration, biomimicry, calcium carbonate, coral, gmo, goethite, kevlar, limpet teeth, materials, science, seashells, silk, spider silk, spiders, stronger than steel