Full Color Light Responsive Diarylethene Inks for Reusable Paper

"Digitalization" represents one approach to shift society's dependence on paper-based communication. However, thus far, this tactic has not had a significant impact on global paper consumption, which has risen over the past few decades. The escalating demand of paper making and consumption has resulted in an intensified negative effect on the environment. Because of this, the development of rewritable paper or erasable ink appears to be an ideal approach to alleviate the increasing demand for paper. In the investigation described herein, novel light-stimulated (UV-vis), reversible color switching, photochromic diarylethene (DE) derivatives are designed, which serve as cyan, magenta, and yellow colored ink materials for full color ink-jet printing. The structures of the DE derivatives are unique in that they contain hydrophilic ethylene glycol chains that enable them to be compatible with aqueous based, ink-jet printing systems. The results of these studies demonstrate that the new DE derivatives can be used in a printing system based on the "write-erase-write" concept that utilizes the same paper multiple times. The approach appears to be ideal for reducing the negative environmental consequences of paper production and consumption.W.J. and M.I.K. contributed equally to this work. The authors thank the National Research Foundation of Korea for financial support (No. 2014R1A2A1A01005862)