A 2-D Polymer

Crystal on its way to becoming a 2-D polymer Max J. Kory et al., “Gram-scale synthesis of two-dimensional polymer crystals and their structure analysis by X-ray diffraction,” Nature Chemistry, 2014. In spite of its looks, this is not the lovechild of an accordion and an earthworm. It is actually a whole new material photographed in the middle of its creation process.

It’s a crystalline material being soaked in a special acid solution. After some days of soaking, the pleats in this structure sloughed off. The resulting sheets were so thin, they were actually 2-dimensional—made of just one layer of atoms. They were among the first 2-dimensional polymers ever made by engineers, Chemical & Engineering News reports. 

This week, two separate research teams published papers announcing they had made the world’s first verified 2-D polymers. The polymer sheets are akin to graphene, a material made of a single layer of carbon atoms. The difference is that polymers are made of atoms of several different elements in a repeating pattern. (In case you’re curious, the two teams made polymers of slightly different atomic compositions.) A 2-D polymer has proved to be more difficult to make than sheets of graphene, which can sometimes even flake off the tips of pencils.

Both graphene and 2-D polymers are being studied for similar reasons, C&EN reports. They could do cool things in optics, and their super-tiny pores mean they could be used in high-tech filters. However, 2-D polymers still need work before they can be used in practical applications. For one thing, engineers will have to figure out how to make more of the polymers. Right now, just making a few grams of the stuff is a big feat, as it’s taken the scientists years to get the process just right.

Both labs had previously made 2-D polymers, but this is the first time they’ve determined the exact structure of the polymers, C&EN reports. How were they able to visualize these vanishingly thin structures? They used X-ray crystallography, the same technique Rosalind Franklin used to visualize a single molecule of DNA in 1952. Franklin’s X-ray image was crucial to James Watson and Francis Crick’s insight into the true structure of DNA.

By: popsci.com