Glassy polymer is a clear conductor of electricity
Researchers at Purdue University have developed a new polymer film that's transparent, looks and feels like glass, and conducts electricity. The material is easy to manufacture on a large scale, should be less expensive than the commonly-used, inorganic indium tin oxide, and is more conductive than other polymers.
It's hard to balance transparency and conductivity in materials. Glass is transparent but an insulator, so in order to make things like smartphone touchscreens, it's often coated with indium tin oxide to make it conductive. Polymers are cheaper to manufacture, but to make them conductive requires chemical doping, an expensive process that wipes out the cost savings and can make them less transparent. So, the Purdue team started with a transparent, non-conductive polymer and modified it to make it conductive.
"Our idea was, could we use polymers easier to make on a large scale but also get them to be electronically active?" says Bryan Boudouris, an author of the study. "The precursors of this new polymer are made on the ton scale. Having a conducting transparent material from carbon-based materials would be significant."
The keys to transparent conductivity were certain radical groups – reactive groups of atoms. The team started with radical groups that were already transparent but not particularly conductive, then simulated how many would be needed to make a polymer conductive.
Based on those simulations, the team synthesized a material that had a higher density of radical sites than in previous studies. The material also needed to be soft enough that these groups could communicate inside it, so the team developed it to flow just above room temperature.
The end result is a polymer that's as transparent as glass, but conducts electricity on the same level as non-transparent conductive polymers. Although the new material isn't as conductive as indium tin oxide, the researchers say that they're currently working on improving the conductivity to close the gap.
The research was published in the journal Science, and the team describes the material in the video below.
Source: Purdue University