Long-Lasting and Easy-to-Use Rewritable Paper Fabricated by Printing Technology

Nowadays, urged by the high demand to reduce paper consumption, rewritable paper receives more and more attention. However, it is a great challenge to conveniently fabricate the rewritable paper which has long legible time of information and is easy to use simultaneously. Here, we report a new type of long-lasting rewritable paper based on color-memorizing thermochromic dye and photothermal-converting toner, which is fabricated by a two-step printing process. The rewritable paper demonstrates excellent rewriting performances (legible time > 6 months and reversibility > 100 times). The thermochromic effect is based on a temperature-driven phase change mechanism, accompanied by a lactone ring tautomerism of crystal violet lactone. The color of the rewritable paper rapidly changes from blue to colorlessness when the temperature is higher than 65 °C, and the colorless state can be maintained at room temperature. The color returns to blue when the temperature is lower than -10 °C. By using an electrothermal pen, a thermal printer, and near infrared (NIR) light, characters and images with high resolution can be handwritten, thermal-printed, and photoprinted on the rewritable paper. The written/printed information can be cleaned under lower temperature or can be quickly erased by NIR light. This rewritable paper is easy for large-scale production and will have promising opportunities in practical applications, such as long-lasting information recording and reading, rewritable label, reprintable displays, and so on.