This Message Will Self Destruct: Scientists Develop Programmable, Self-Erasing Documents
Researchers are harnessing nanoparticle properties to develop fading ink Remember when, as a kid, you would pass “top-secret” notes written in lemon juice that your friends could only read in the right light? Well, in light of new nanotechnology research, this now sounds absurdly antiquated, like cave painting in the modern era. Instead, the youth of the future (and adults, too) could have to option to communicate via documents that self-erase at a programmed time. The idea comes from Northwestern University, where a team of researchers led by Bartosz Grzybowski is making use of a unique property of certain nanoparticles-–their ability change color based on how close they are to one another. So, when spread out, gold nanoparticles are red, but once you pack them together, they turn violet, blue, and then become colorless. To change the distribution of the particles, you can coat them with...