You are currently browsing the tag archive for the ‘molecular engineering’ tag.

Vanilla Ice on 10/1/90 in Minneapolis, Mn. (Photo by Paul Natkin/WireImage)

Back in college I took a course on planetary and atmospheric dynamics. Although I don’t recall the course as well as I should (the class was extremely mathematical for my taste), one concept which has remained with me is is “albedo”–how well the planetary surface reflects solar radiation back into space. Albedo was a strange wild card in everyone’s computer models of planetary temperature and climate. Small changes in planetary albedo could lead to big temperature changes across the globe (as say when high-albedo ice sheets melt or when reflective white clouds form). Albedo isn’t just important in astrophysics: how well a surface reflects or absorbs radiant energy has engineering and economic implications down here at a human scale as well.


This awkward lede is an attempt to contextualize the potentially enormous importance of today’s color-themed topic. Researchers at Purdue University have invented a very, very bright shade of white paint. The color is so white that it reflects 98.1 percent of visible light. The color (which lacks a name, but should be called something like “great white”, “polar bare”, or “super dazzle”) is so radiant that surfaces painted with the compound are cooler than the ambient temperature of things around them. It is the polar opposite (snicker) of the ultra-black developed a few years ago.

The secret to this color is a molecular engineering trick. Barium sulfate is a safe and commonly used white pigment for makeup and coated papers. Engineers created a range of microscopically sized barium sulfate particles and then combined these differently sized particles into a single coating. The result was this glistening mirror white.

white glitter christmas abstract background

Now I can’t show you this color in a photo (since it wouldn’t make any sense on the luminous medium of your computer screen), but I get the sense that, like that super black, it has an unearthly look to it in the real world. Speaking of the real world there is no news yet on practical or saleable applications of the incredible ultra white (which makes me think it might prove hard to produce at scale). Yet the fact that it exists is exciting for engineers (and artists too). Let’s get to work making some more of this stuff so we can find out if is any good…and so we know whether we can solve our climate problems by painting Nevada and the Kumtag Desert shiny white!

A Human Holding a Small Limpet

A Human Holding a Small Limpet

We live on the threshold of an era of stupendous nanomaterials! In the near future, molecules will be engineered to be harder than diamonds or stronger than steel…yet these miracle materials will also be workable and light.

Artist's Conception of a Space Elevator--one of the miracles which should be possible through nanotechnology

Artist’s Conception of a Space Elevator–one of the miracles which should be possible through nanotechnology

Well, at least that’s what they keep telling us. In practice our best nano-materials do not seem capable of besting nature in the truly important categories—like hardness, tensile strength, or elasticity (or, if our synthetic materials are superior, they prove difficult to build into structures which fully exploit their strengths). A case in point comes from the lowly yet resilient limpet. Limpets are marine gastropods (snails) which have shells without visible coils. Actually, the name “limpet” is an informal common name—scientists have a very different way of characterizing these mollusks.

Common limpets (Patella vulgata) adhering to tidal zone rocks

Common limpets (Patella vulgata) adhering to tidal zone rocks

Limpets cling tenaciously to rocks at the tidal line by means of a muscular foot designed to create suction. They also produce an adhesive mucus which helps the foot adhere to whatever surface the limpet wishes to cling to. They carefully scour their ocean rocks for nutritious algae with a radula—a tongue-like rasping organ covered with teeth. Limpets have been of note to humans principally as a metaphor for resilience…or as a nuisance. Yet scientists experimenting on a common limpet, Patella vulgata, found that the little snail’s teeth had greater tensile strength than spider silk. Indeed, limpet teeth are the strongest known material in the natural world and approach the tensile strength of our strongest carbon fibers. With these teeth the little snail can (and does!) chew through rocks.

A (horrifying) microscopic picture of limpet's teeth

A (horrifying) microscopic picture of limpet’s teeth

The secret to the limpet’s mighty teeth is a miracle of molecular design in its own right. The cutting portion of the teeth are composed of fibers of goethite (a sort of iron hydroxide named after the great German poet). These fibers are under 60 nanometers in diameter—a size which allows them to be tremendously strong. The teeth are technically a composite–since the tiny goethite fibers are held together by chitin, a natural polymer (which the exoskeletons of insects are made of).

This evil henchman was the best character.

This evil henchman was the best character.

Technically there are human-created carbon fibers stronger than the astonishing teeth of the limpet, but these fibers can only be utilized in certain configurations and fashions–so the limpets’ teeth are of very real practical interest to materials scientists. Engineers are already working on duplicating the little snail’s teeth for mining and cutting equipment…and for human dental uses. Perhaps we really could someday have some of the powers of Jaws, the lovable hulking henchman from seventies James Bond movies. With our synthetic chompers we could bite through rocks and steel cables. Uh, wouldn’t that be wonderful?

Ye Olde Ferrebeekeeper Archives

November 2021