Wow... this stuff is impressive.
It is silver-based. They claim no shaking, no clogging and that it dries "instantly".
A single pen costs $20.
Maximum current is quoted as 175mA, but it isn't clear how wide the trace must be. The way it
looks, I would assume that is for a single line of ink. They indicate that on smooth surfaces like
photo paper, it can carry a lot more current (800mA on photo paper).
They also make resistor ink pens that will have a resistance of 100 to 100k ohms per cm (depending on which
pen you buy).
Victor, since it can write on photo paper, maybe it will stick to plastic. There's only one way to find out.
(Mine's on the way. I'll blow $20 to find out.)
http://www.electroninks.com/faq/