I’m not going to lie. Sometimes I see a science paper and think, dang, that’s really cool, I really wish it could do X. Like, maybe a major advancement in flexible, transparent plastic conductors could solve all of my cracked smartphone screen problems. Of course, things are more complex than just that, and a single new material won’t solve my concrete-induced woes. But this latest research definitely conjures some intriguing possibilities.
“Conductive flexible plastics will open up a host of medical and display applications that we can’t currently imagine,” Brett Savoie, assistant professor of chemical engineering at Purdue University, told Gizmodo. Combined with other breakthroughs, plastics that conduct electricity well could make for some wonderful gadgets.
Scientists have increasingly been exploring the field of “organic radical polymers,” which have strange electronic properties. These are molecules built from a single regular repeating unit, called a monomer. But their special electrical properties come from a dangly bit hanging off of each monomer that has an extra, unbound electron, called a free radical. This new polymer, poly(4-glycidyloxy-2,2,6,6-tetramethylpiperidine-1-oxyl), PTEO for short, is in the neighbourhood of 10,000 times more conductive than its competition.
Building one of these conductive polymers requires precisely controlling each monomer. In this case, the conductivity comes about through annealing, or heating and slowly cooling the material. This presumably arranges the polymer in a way that allows the electrons to move from free radical to free radical along a little electric highway.
This isn’t the first transparent conductor, nor the first polymer conductor. But lots of the existing ones rely on a chemical called ITO, which incorporates the very expensive and brittle metal indium. The new PTEO is not the most conductive plastic, but it takes a lot less work to make than other varieties.
The research has other limitations—the conductivity only works on teeny, micrometer-scale distances.
As Professor Jodie Lutkenhaus from Texas A&M writes in a commentary for Science, “Although the conductivity is exceptionally high for this polymer type, wider application will require this conductivity to be sustained over a larger length scale.” She’d also like to see further analysis of the polymer’s structure to validate the author’s claims in their paper, also published in Science.
In order to be used in a flexible touchscreen, this material probably needs to be combined with another flexible piece, the same way that a transparent, inflexible sheet of glass covers the transparent, inflexible conductor in your iPhone.
The new conductive plastic is constructed from some pretty widely available parts. If the researchers could send the electrons through the conductors over longer distances, perhaps they could incorporate the material into batteries, flexible touch screens, or medical devices.
Maybe it’s spring fever, but I’m feeling optimistic that one day I’ll have an iPhone that, with the help of some neat chemistry, doesn’t crack in response to my own stupidity. [Science]