California chemists develop rewritable paper

It's often said that we're living in the Digital Age. But even Internet startups use paper. In fact, some research suggests businesses continue to retain 90 percent of their information on paper -- paper that is routinely thrown away after just a single use.

If that sounds wasteful, that's because it is. It's waste that contributes to deforestation and all types of pollution. And it's waste that chemists at the University of California, Riverside say could be prevented (or at least lessened) with the advent of "rewritable paper." Researchers there have developed such a thing.

The novel product has been successfully fabricated in the school's labs. The paper doesn't require ink, but instead uses ultraviolet light to stain letters onto a plastic film of light-reactive chemicals known as redox dyes. The ultraviolet light photobleaches the negative space on the film, reducing most of the dye to its colorless state and leaving only the letters and images behind.

The film paper can be returned to its fully saturated color state with just a simpe heating. Each piece can be erased and written on again twenty or more times with no compromise in contrast resolution.

According to environmental advocacy group Forest Ethics, North America is still the number one paper consumer on Earth, using nearly 500 pounds of paper per capita annually. With demand for paper on the rise in much of the world, paper production is expected to account for nearly half of all logging in the near future. Rewritable paper has the potential to reverse these trends.

"This rewritable paper does not require additional inks for printing, making it both economically and environmentally viable," Yadong Yin, a professor of chemistry who oversaw the lab work, explained in a press release. "It represents an attractive alternative to regular paper in meeting the increasing global needs for sustainability and environmental conservation."

"The printed letters remain legible with high resolution at ambient conditions for more than three days -- long enough for practical applications such as reading newspapers," Yin added. "Better still, our rewritable paper is simple to make, has low production cost, low toxicity and low energy consumption."

The work of Yin and his colleagues -- which was conducted with the help of grant funding from the Department of Energy -- was detailed this week in the journal Nature Communications.