The paper of the future
More than 500 million tons of paper have been produced in the world this year, according to The World Counts. Their production is linked to deforestation, the use of energy and water as well as pollution and waste problems.
In average we use more than two pieces of paper for everyone on the planet every single hour, and its demand is expected to double between 2005 and 2030. Also the pulp and paper industry is the single largest industrial consumer of water in the Western countries with 10 liters of water needed to produce a single A4-sheet of paper.
With this in mind researchers from the National Engineering Research Center for Colloidal Materials from the Shandong University in China developed ‘the paper of the future,’ as it names it Science Magazine.
The paper consists in a rewritable paper-like surface that can be printed and erased up to 40 times without any loss in resolution. The surface is ‘printed’ by selectively exposing it to UV light which makes the colorless surface to turn blue. It is made out of tungsten oxide which is currently used in smart windows that modulate the amount of sunlight passing through and a water-soluble polymer.
The process takes just a matter of seconds, faster than any previous experiments with rewritable surfaces. The printed pattern (like seen in the pictures) can remain visible as long as ten days in normal atmospheric conditions before it fades away. Also it can be bleached in about half an hour by exposing it to heat or ozone.
“Ink-free rewritable media has attracted great attention as a potential alternative to current paper prints, owing to its benefits to reducing paper production and consumption for environmental protection,” reads their article. It was published in ACS’s publication Applied Materials and Interfaces under the name of ‘Electrospun Photochromic Hybrid Membranes for Flexible Rewritable Media.’
According to the authors this technology could be easily commercialized. “As-formed photochromic membranes are low-cost, environmental benign and easy for large-scale production, indicate their great potential as flexible rewritable media for practical usage,” conclude the authors.