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Tunable reverse photochromic materials for rewritable devices

Researchers from the CSIC and the UAB university, in the Nanosfun group at the Catalan Institute of Nanoscience and Nanotechnology (ICN2) have developed a straightforward strategy to obtain solid materials which change colour when they are exposed to visible light. These materials might find application in multicolored rewritable devices.

Image of the solid materials with highly tunable photochromic performances, obtained in the research (Nanosfun/ICN2).These new materials have tunable reverse photochromism, in other words, they decolorate  when they are exposed to a light and recover the initial colour in the dark.

They are based on microcapsules of core-shell structure. The core contains dyes dissolved into phase-change-materials (PCM) that directly or indirectly induce the formation of the colour. The external shell of the microcapsule is made of polymer.

The solution of the dyes in phase-change-materials (PCM) is designed to develop the color of the dyes in the dark, without irradiation. The irradiation of these inks with visible light (white-light lamps, sunlight, visible laser pointers...) produce their reversible discoloration.

These materials might find application in multicolored rewritable devices or in strategies for fighting counterfeiting

A simple variation of the capsules content (the PCM or the dye) allows an easy tuning of the initial color and recoloration rates of the final ink, paint suspension or powder. The strategy enables a freely tuning of the components (PCM, photochrome or polymer) and it is based on commercial products.

“Just changing the content of the capsules, the dyes or the PCM material, it is posible to adjust the color as well as the coloration/decoloration rates of the final ink, paint suspension or powder”, say the scientists.

“These capsules could be integrated in papers or plastic materials, as we demonstrated in one example, yielding solid materials with highly tunable photochromic performances. These materials might find application in multicolored rewritable devices, or in strategies for fighting counterfeiting."

Nanosfun group, ICN2.

Reference article: https://pubs.acs.org/doi/10.1021/acsami.8b22335

Contact:

Isabel Gavilanes-Pérez, PhD.
Deputy Vice-Presidency for
Knowledge Transfer
Spanish National Research Council
(CSIC)
Tel.: +34 – 93 594 77 00
This email address is being protected from spambots. You need JavaScript enabled to view it.

Researchers from the CSIC and the UAB university, in the Nanosfun group at the Catalan Institute of Nanoscience and Nanotechnology (ICN2) have developed a straightforward strategy to obtain solid materials which change colour when they are exposed to visible light. These materials might find application in multicolored rewritable devices.