Materials for a greener tomorrow!

Kit Behard finds that nanofoams, Stanene and Shrilk may be the keys to a sustainable future

Goodbye Plastic?

Plastics are arguably the most important material of the 20th century. Since the invention of the first synthetic plastic in 1907 (Knight, 2014) they’ve been used in everything from toys and packaging, to electronics and transportation. The reason for the versatility and wide use of plastics is that they are flexible, strong and cheap. However, an average plastic bottle will take 450 years to decompose! It’s time for Shrilk to step in. Made from chitin, the second most abundant organic polymer, and fibroin, a protein found in spider silk, Shrilk is flexible, tough and able to decompose within weeks (Crystall, 2014)! However, it currently requires funding to reduce its cost.

The World’s Lightest Solid

In 1930, Samuel Kistler invented “aerogel” by removing the liquid from a silica gel (Crystall, 2014). The resultant solid consisted of a fine skeleton; the other 99% was air. Recently, the environmental potential for similar nanofoams (materials with this skeletal structure) has been discovered. For example, beryllium nanofoams can store hydrogen and would be an effective fuel store for hydrogen-powered cars. There are also signs that copper nanofoams could be used for sucking carbon dioxide out of the air!

Step Aside Superconductors!

Superconductivity, the property of having no resistance when conducting electricity, was first observed in 1911. Unfortunately it seemed to only occur in superconductors at temperatures close to absolute zero. A century later and the most recent breakthrough has seen superconductors work at -70 degrees Celsius (Barras, 2015). However, there is hope of observing superconductivity at room temperature, but in a new class of material called topological insulators. These materials allow electrons to move freely on their surfaces and due to a quantum interaction known as spin-orbit coupling they are unable to tunnel deeper into the material or perform a U-turn (Crystall, 2014). They are forced to fly up one side of the material and back down the other. Stanene, a 2D sheet of tin, takes this one step further. Since it is only one atom thick, it restricts the electrons’ movements, forcing them to speed up and down the edges - even at room temperature! Currently Stanene is purely theoretical, but its synthesis is expected shortly.

In my opinion, these materials, and others like them, have properties that have been long-awaited and are becoming increasingly necessary. Shrilk could be a key factor in ending the expansion of landfills. Metallic nanofoams may be an important solution to the problem of hydrogen storage, leading to decreased dependence on petrol. And materials like Stanene are sure to cause exciting developments in the world of electronics. I think it’s highly likely that the next jump in technology will stem from the synthesis of some new and peculiar material, perhaps one of those mentioned in this article.

From Issue 10