This text will disappear after 60 seconds.

American chemists have invented a new way to create self-destruct documents. They used gold nanoparticles coated with a layer of azobenzene molecules. When exposed to ultraviolet light, these nanoparticles become polarized and form clusters, and the substance of such nanoparticles first changes its color from red to blue, and then becomes completely colorless. Thus, if you make a red film with such a substance (nanoparticles are inside the gel, sandwiched between layers of transparent plastic), then you can “print” the blue text on the film with an ultraviolet ray in a couple of seconds, and this text will disappear by itself.



Using special techniques, you can even make colorful pictures.
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The lifetime of the text depends on the amount of azobenzene in the coating of nanoparticles. By changing the concentration, you can increase the lifetime of the text from a few seconds to several hours and even days.

The research results are published in the journal Angewandte Chemie, DOI: 10.1002 / anie.200901119 .

via New Scientist