A new type of solid-state photoreversible colour-switching system made from Prussian blue nanoparticles and titanium dioxide nanoparticles has been created by a team of researchers at Shandong University in China and the University of California at Riverside in the US. The material can be used to make an ink-free, printable, rewritable paper that has the same feel and appearance as conventional paper but which can be written onto and erased more than 80 times without the need for additional ink……….
http://nanotechweb.org/cws/article/tech/67315