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 photo thermal-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 degrees C, and the colorless state can be maintained at room temperature. The color returns to blue when the temperature is lower than -10 degrees 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.