Secret Messages Hidden In Photosensitive Polymers

Scientists from the CNRS and Aix-Marseille University have just highlighted the interest of light sensitive macromolecules: exposed to the right wavelength of light, they can be transformed to allow to modify, erase or decode the message molecular they contain. The results of this research are published September 4, 2019 in the journal Nature Communications .

DNA is a long chemical sequence on which genetic information is stored:. Inspired by this biological system, many research teams have been exploring in recent years how to store and then decode information in synthetic macromolecules, also called polymers ¹ .

Further progress in this area, researchers from the Charles Sadron Institute (CNRS) and the Institute of Radical Chemistry (CNRS / Aix-Marseille University) have developed photosensitive polymers allowing the light modification of information stored at the same time. molecular scale. Three types of information corruption have been highlighted in these works: revealing a message, modifying it or erasing it.

French scientists have shown that some polymers can act as invisible ink: exposed to the appropriate wavelength, their monomers are transformed and the sequence becomes readable. The message therefore only appears if it is subjected to the right light source, it is the first example of a secret message stored on a molecule. Their study also shows that the modification of monomers by light can be used to erase or modify the information contained in certain polymers. For example, chemists have "transformed copper into gold" by changing the chemical symbol of copper "Cu" inscribed on a polymer in "Au", the chemical symbol of gold.

The reading of the polymers is then done by mass spectrometry, a technology already used routinely in many laboratories of analysis. The teams involved in these recent works now wish to pursue them by exploring the control of the physical properties of polymers by light, for applications other than the storage and decoding of information such as the design of new materials.

¹ A polymer is composed of simple chemical units, the monomers. Thus, a polymer can take the form of a sequence of two different monomers that can be read as the 0 or the 1 of a written message in computer binary language.