Self-Erasing Documents Coming Sooner Than You Think


Tired of Tom Cruise sneaking through your evil corporation’s ventilation ducts and snapping photos of your nefarious W-9 forms? Research into the unique properties of certain nanoparticles may have a clever solution for you in the form of documents that erase themselves.

While the Mission: Impossible reference from which I drew my Tom Cruise allusion relied entirely on documents, audio cassettes and microfiche programmed to physically detonate alongside a timer, the technology being crafted at Northwestern University is decidedly more subtle.

By coating gold nanoparticles with “a layer of hair-like molecules called 4-(11-mercaptoundecanoxy)azobenzene,” the researchers have created a hybrid material able to conform and maintain specific shapes based on its creator’s commands. Not only could the researchers build long strings of words using these ambulatory particles, they were also able to alter the color of the material itself simply by shifting the concentration of nanoparticles in any one area.

“The colour of the nanoparticles depends on how close they are to one another,” lead researcher Bartosz Grzybowski told New Scientist. “For instance, gold nanoparticles are red when separated, but become violet, then blue, then colourless as they cluster together.”

The most useful part of this breakthrough however, is not in its ability to create shapes and colors, but in their nanoparticulate tendency to revert to a neutral form after fulfilling their goal. Only a few minutes away from the ultraviolet signal causes the nanoparticles to revert to their original shape.

With that in mind, the potential for self-destructive memos pales in comparison to the idea of hyper-miniaturized computer processor components able to alter their shape and function at a moment’s notice and with a minimum of energy loss.

(Image: Paramount Pictures)

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