Currently, paper production and disposal have a large negative impact on the environment: paper production is a leading source of industrial pollution, discarded paper is a major component (approximately 40%) of landfills, and even recycling paper contributes to pollution due to the process of ink removal. There is also the issue of deforestation: in the US, about one-third of all harvested trees are used for paper and cardboard production.
Working to address these problems, researchers have been investigating alternatives to disposable paper. One possibility is to take advantage of the color-switching ability of certain chemicals when exposed to light, although in the past this approach has faced challenges in terms of stability, limited reversibility, high cost, toxicity, and difficulty in applying the coating to ordinary porous paper.
Nanoletters - Photocatalytic Color Switching of Transition Metal Hexacyanometalate Nanoparticles for High-Performance Light-Printable Rewritable Paper