Scientists Have Invented Paper That You Can Print With Light, Erase With Heat, and Reuse 80 Times (qz.com)

An anonymous reader quotes a report from Quartz: Nearly 1% of carbon emissions annually can be attributed to paper production, even though we recycle much of the paper we produce. Yadong Yin has a solution. He and his colleagues at the University of California at Riverside have invented a type of paper that can be printed on using just light, erased by heating, and reused up to 80 times. Yin created nanoparticles, which are a million times smaller than the thickness of human hair, with the dye Prussian blue, or its chemical analogues, and titanium oxide, which is commonly used in white wall paint. This mixture is then applied to normal paper. When the coating is exposed to ultraviolet light, electrons from titanium oxide move to the dye in the nanoparticle. This addition of electrons makes the blue dye turn white. Focusing the ultraviolet light into shapes, you can print white words on a blue background -- or blue words on a white background, which are easier to read. If left alone, the paper reverts to its original state in five days. That process can be accelerated by heating the paper to 120 C (250 F) for 10 minutes.

Comments

New printer

[religionofpeas]

Now all we need is a new printer that doesn't jam when the paper is not perfectly smooth.

Re:New printer

[AmiMoJo]

Paper has some useful properties that help it remain popular. If we can replicate or better these properties with technology, we can finally go paperless.

Cheap, disposable: Compared to a tablet computer, paper is very cheap and damage is rarely a big deal.

Just works: No battery to charge, folds up if required, can be marked with any pen or pencil and there is no UI to learn or fumble with.

Permanent: People trust printed documents not to change and signatures/stamps count for something.

Archival: Paper lasts a long time, and people know how to protect it. Digital files get lost, formats go obsolete and unreadable, same for the storage media. Backup still seems to be hard compared to "file in fire-proof safe".

Size: Even just A4/letter size tablets are expensive, let alone A3. Larger sizes can't be folded either.

Compatibility: Different tablets have different ways of distributing and accessing documents.

There are a few areas where paperless wins. Machine translation is getting very good. But it's still a struggle. Where I work we are replacing paper drawings with Raspberry Pi and monitors, basically glorified PDF readers. It only works because our CAD documents are exported to PDF for easy viewing and stored on a file server somewhere, but it's far from a turnkey, universal solution.

Re:Sounds useless

[omnichad]

It can be reused/reprinted 80 times. It doesn't say it will stay wrinkle/crease free for 80 reuses. And when it does get thrown out, it's full of ferric ferrocyanide, which is fairly toxic.

Any amount of wear on the paper and nobody will want it second-hand. Or, nobody will buy their own paper because it's too expensive. They just won't return the paper back to the convention staff, etc.