Inkless Rewritable Paper Innovated

Printing doesn’t have to cost a lot of money on paper and inks in the future.

So says Yadong Yin(pictured), chemistry professor at the University of California, Riverside.

According to seeker.com, Yin and other colleagues from Shandong University in China as well as Lawrence Berkeley National Laboratory have figured out a way to make paper that can be printed with ultraviolet light, erased by heating it and then rewritten more than 80 times.

It is said that rewritable paper could be used to make newspapers, notepads and price tags, which can be rewritten when the amount changes.

It is reported that two types of nanoparticles are utilized to make this inkless paper, including those made of Prussian blue, a common nontoxic blue pigment, and titanium dioxide, a nontoxic chemical used to print the white M&Ms label on the candies. Both types of nanoparticles can respond to light. Mixing these two kinds of nanoparticles in a solution will turn the conventional paper to deep blue when coated with a thin layer of the nanoparticles.

To print text, the scientists used a mask with the letters etched out and placed it on top of the coated paper. When exposed to ultraviolet light, the photons in the light hit the titanium dioxide nanoparticles through the cut-out holes in the mask, and the nanoparticles then released electrons. Those electrons got picked up by the Prussian blue nanoparticles, which then turned colorless.

Besides the mask overlay, a prototype printer has also been developed to produce inkless printings. The scientists expect to develop a printer that can print on standard-sized papers and take the system to full color.

The inkless letters are said to remain visible for at least five days and can be erased easily by exposing the page to heat for 10 minutes.

Click here to send us your news.