Got a secret. Can you keep it? Swear this one you'll save...
Liang Li at Shanghai Jiao Tong University in China and colleagues created a new invisible ink by accident. They were initially trying to synthesise a certain glowing nanomaterial when they've produce an invisible lead compound. And when mixed with particular salts, such can become visible again.
And while such invisibility for letters has already been utilized before, this new one is different as it doesn't leave any residue behind once legible. Remember when you use those invisible-inked pens on a piece of paper and just have to hold it up to a light for you read? That wouldn't possible with this new ink at all. Also, the ink can be used in a modified office printer!
This may seem to be just a little child game or useless trick, but this is actually very useful in protecting one's documents and preventing counterfeits. “This invisible ink can be used to record and protect confidential information by printing process,” Li says.
However, it is not to be forgotten that lead is toxic. So while this sounds great, the sender or recipient could be at risk. The team, tough, is trying to find alternatives for such like tin, which is immensely less toxic than lead.
Li Tan at the University of Nebraska-Lincoln even says the lead compound easily dissolves in small amounts of water and could even break down, itself, when used repeatedly. “The work itself is solid, no doubt about it,” Tan says. “The question is, how many times can you use it?”
Well, we still have this invisible-poison-letter dilemma in here. However, as long as researchers get to find another similar mixture with less toxicity, don't you think this would really be helpful and exciting way to hide important papers?
Get weekly science updates in your inbox!