Xymox uses PEDOT (or more accurately PEDOT:PSS) to make capacitive sensors. We use a film version supplied by Kodak called KODAK ESTAR Highly Conductive (HCF) Films to make transparent sensors used over displays and a screen printed version supplied by Heraeus called Clevios to make translucent sensors used in backlighting applications. To keep the family together, Kodak actually coats Heraeus Clevios PEDOT.
So what is PEDOT?
poly(3,4-ethylenedioxythiophene):polystyrene sulfonate
Yeah. That’s a mouthful. Impress your friends at the bar and throw that word around. “It was crazy. We had a big neighborhood party going on and the nutty professor guy at the end of the street breaks out this can of poly-ethylenedioxythiophene-polystyrene-sulfonate….”
PEDOT is a flexible transparent material (like a lot of stuff) that is also conductive (not like a lot of stuff). Applying a layer of PEDOT to other materials makes them conductive. It’s applied as liquid and after drying remains flexible, very flexible.
PEDOT, invented in the late 1980s, was first used as an anti-static for photographic film. Yep, that film running through the projector at 24 frames per second (which coincidentally is just a hair over 1 mph) creates a lot of static. To make sure the kid in the projector booth does not get shocked, the film is coated a PEDOT (remember, it’s conductive) to dissipate all that static. Film may not be as popular today as previous, but anti-static coatings used for packaging are more important than ever in protecting electronic components and devices. Electrolytic capacitors (like those used in virtually every electronic device) also use PEDOT. More recent applications include OLEDs for displays and lighting, photovoltaics, smartwindows and, of course, capacitive sensors.
PEDOT continues to find new applications and expects to be around for long time.
The history of PEDOT courtesy of Heraeus.
