Transparent, conductive and printable plastic

A team of chemists and engineers from the Georgia Institute of Technology succeeded in developing a polymer capable of conducting electricity with high efficiency while being flexible, transparent and easy to use on an industrial scale

[Translation by Dr. Moshe Nachmani]

A team of chemists and engineers from the Georgia Institute of Technology (Georgia Institute of Technology) succeeded in developing a polymer capable of conducting electricity with high efficiency while being flexible, transparent and easy to use on an industrial scale.

The researchers were able to produce this innovative and important polymer simply by removing the non-conductive material from the rest of the conductive material. The resulting process could give rise to new types of flexible and transparent electronic devices, such as wearable biodetectors, organic photovoltaic cells, as well as screens and glasses based on virtual reality.

"Our original idea was to take a conductive component that we coated with a non-conductive material, then we thought why not just get rid of it and stay with the conductive component only," said the lead researcher. "It is a simple idea, and yet there were many points in it that we could simply fail at for many reasons. However, we discovered that it really works, and even better than we expected." In order to make a strip of plastic conduct an electric current, chemists start with a known polymer backbone - in this case a common polymer called PEDOT used in industry in certain applications. This polymer is excellent for conducting electricity, but it is difficult to use in its original form due to the fact that it is not soluble. However, when side chains are added to this polymer, it can be dissolved and used in printing ink or spray paint applications. This modification makes the polymer easy to use and apply. Unfortunately, these side chains are essentially a wax-like material that does not conduct electricity. "If you think about electrical conductivity, imagine a copper wire; He is beautiful and attractive. And then if you coat it with wax, it is not so conductive, there is a certain barrier inside it," said the chief researcher. "Our idea was this - we are interested in the presence of these side chains during the process, but not in the final product. So we added side chains that, once we're done with the process, can be easily removed." In other words, the researchers created a polymer with side chains that could be used to print or spray, chemically detach the side chains and wash them out with common industrial solvents. After a final conversion step, the result is a flexible and highly conductive polymer, stable and impermeable to water or other solvents. The research team utilized knowledge from a variety of scientific fields such as: mechanical engineering, chemistry, biochemistry, materials science and engineering. The research findings were published this year as part of articles in two journals in the field of chemistry, Journal of the American Chemical Society also applied Chemistry.

"This idea that we thought of for a method to make a polymer with a conductivity of more than a thousand segments per cm, capable of being produced using simple industrial printing methods and common solvents, and in addition to being electrically conductive, also optically transparent, is just so exciting for me," said John Reynolds, a professor in the School of Chemistry and Biochemistry and one of the authors of the two articles. The research team is already getting a lot of attention for their innovative material, which they call PEDOT(OH), and for which a patent application has been submitted. The researchers are also meeting with partners from the industry who are interested in obtaining a license for the new technology thanks to several advantages of the polymer.

One of the most common transparent conductive materials in the production of flat screens, photovoltaic devices, smart windows and other applications, is indium tin oxide. However, this material has several disadvantages. "It is quite difficult to create curved and flexible devices using indium tin oxide material since this material is brittle and tends to crack," said the researcher. "These polymers we created are mechanically flexible. There is a whole field called 'bioelectronics', in which people place electrical devices on the skin and as implantable devices, a field where mechanical flexibility is extremely important.

"One of the real benefits of our idea lies in the fact that the researcher has great control over the processing of the material," said the lead researcher. "From an industrial point of view, the greatest benefit in the field is that if you want a layer twenty nanometers thick, you can easily produce it; And if you want a layer one micron thick, you can easily produce that too; You really have a lot more control." The heart of the researchers' idea is actually a combination of the appropriate type of polymer skeleton with the appropriate type of degradable bond for the required application, high electrical conductivity in this case, said the lead researcher.

The news about the research 

Article Summary

More of the topic in Hayadan:

• A plastic capable of conducting electricity
• Researchers from Tel Aviv University have developed a new type of waveguide
• The first measurement of electric current in a molecular wire
• Learn from the butterflies about full transparency