Blowing On Money To Tell If It Is Counterfeit

HughPickens.com writes Scientific American reports that simply breathing on money could soon reveal if it's the real deal or counterfeit thanks to a photonic crystal ink developed by Ling Bai and Zhongze Gu and colleagues at Southeast University in Nanjing, China that can produce unique color changing patterns on surfaces with an inkjet printer system which would be extremely hard for fraudsters to reproduce. The ink mimics the way Tmesisternus isabellae – a species of longhorn beetle – reversibly switches its color from gold to red according to the humidity in its environment. The color shift is caused by the adsorption of water vapor in their hardened front wings, which alters the thickness and average refractive index of their multilayered scales. To emulate this, the team made their photonic crystal ink using mesoporous silica nanoparticles, which have a large surface area and strong vapor adsorption capabilities that can be precisely controlled. The complicated and reversible multicolor shifts of mesoporous CPC patterns are favorable for immediate recognition by naked eyes but hard to copy. "We think the ink's multiple security features may be useful for antifraud applications," says Bai, "however we think the technology could be more useful for fabricating multiple functional sensor arrays, which we are now working towards."

Comments

High security

[Anonymous Coward]

Where on earth would anyone get hold of a ink jet printer?

Re:High security

[ArcadeMan]

I don't know, everyone is ripping them apart for parts to make a 3D printer!

Why worry?

[Patent Lover]

Counterfeiting is illegal.

Life lessons from craps

[PopeRatzo]

This isn't so crazy.

I know for a fact that having a hot girl blow on my dice helps me make that eight the hard way.

Re:Life lessons from craps

[mister_playboy]

That's a halfhearted moisture application. Have her put them in her mouth instead so you get the full luck application.

Hard to copy?

[manu0601]

They did it in the lab and published about the method, then how would it be hard to copy?

Re:Hard to copy?

[TubeSteak]

By adjusting the size and mesoporesâ(TM) proportion of nanoparticles, we can precisely control the original color and vapor-responsive color shift extent of mesoporous CPC. As a consequence, multicolor mesoporous CPCs patterns with complex vapor responsive color shifts or vapor-revealed implicit images are subsequently achieved. The complicated and reversible multicolor shifts of mesoporous CPC patterns are favorable for immediate recognition by naked eyes but hard to copy.

I assume that if you can't come up with the exact size/proportion of nanoparticles, you won't get the same color shifting effect and your counterfeit will not pass as real.
It's certainly better than the current security measures which mostly rely on restricting access to the materials and equipment necessary to make fake currency.

Re:Old News...

[morgauxo]

Umm, as it cools off? This is a humidity sensing ink, not a temperature sensing one.

Don' t ask me why one is better than the other. But.. definitely not the same thing.

Re:Let me get it straight

[wonkey_monkey]

If a crafty person prints $20 bill on the printer, he is a criminal and a counterfeiter.

When central banks create money by simply changing the numbers in the computer, it is called quantitative easy.

Yes. That's how money works.

It's no less weird that we have rules like this than it is to agree that little bits of paper are worth anything at all in the first place.