Even better than Erasable Paper (aka Transient Paper) would be Programmable Erasable Paper, Paper that can be programmed to self-erase after a certain period of time!
That is the promise of a new technology developed by Northwestern University. A team of researchers is leveraging the unique property of certain nanoparticles – their ability to change color based on how close they are to one another - by coating them with certain molecules (MUA, also known as aka 4-(11-mercaptoundecanoxy)azobenzene by some but not me :-)), so that they change position under UV light.
The printing process is similar to Transient Paper – beam UV light to print an image. This new technology, once well mastered, should allow the disappearance of the ink to be more “programmable” – by changing the amount of MUA coating, that speed will vary (whereas Transient Paper is a standard 16-24 hours). These nanoparticles should also provide more color options (although probably limited to shades of purple, blue and red based on this New Scientist Article).
Right now it does not have the look and feel of Real or Transient Paper (two sheets of plastic with gel in between) and the “program” speed depends, just like Transient Paper, on external conditions such as lighting and temperature. However, this is very promising technology as a replacement for paper, that could bring us one step closer to the “Less Paper Office” a and a sustainable use of paper.