A polymer, that is. The new Canadian banknotes are made of... plastic.
I've used these Canadian-made polymer banknotes in Zambia. All the ink on the older bills wore or fell off, and you would go around with these silvery slidey things in your pocket trying discern whether it was a 1,000 Kwatcha note or a 20,000.
I think they've improved the technology since then.
On the negative side, they are unfriendly to life-forms.
Expect howls of rage from the environmentalists as Canada introduces these killer-banknotes.“Further, scientific evaluation has shown that there is significantly less bacteriological growth on polymer banknotes, and that any bacteria which gets onto the notes quickly dies because of the lack of nutrients on the non-porous and non-fibrous material.” Source: Securency International Pty Ltd.