A remarkable new paper made from cellulose fibers could be strong enough to one-day replace metal.

The paper gets tougher and stronger the smaller the fibers get, and researchers are hopeful that it could fulfill the need for a material that is both resistant to non-recoverable deformation and tolerant of damage, the University of Maryland reported.

"Strength and toughness are often exclusive to each other," said Teng Li, associate professor of mechanical engineering at UMD. "For example, a stronger material tends to be brittle, like cast iron or diamond."

Cellulose is the "most abundant renewable bio-resource on Earth," and can be used to create incredibly tough and strong materials. To make this promising new type of paper, the researchers used several sizes of cellulose fibers that are all too small for the naked eye to see. The paper, made of 10-nanometer-thick fibers, was found to be 40 times tougher and 130 times stronger than conventional notebook paper, which is made of cellulose fibers thousands of times larger.

"These findings could lead to a new class of high performance engineering materials that are both strong and tough, a Holy Grail in materials design," Li said.

These materials could even be used to replace metals and other structural materials, potentially leading to the creation of new energy efficient vehicles. Transparent cellulose nanopaper could be used as a functional substrate in flexible electronics for use in applications such as "paper electronics, printable solar cells and flexible displays." The material could help improve the performance of carbon nanotube paper.

"Paper made of a network of carbon nanotubes is much weaker than expected," Li said. "Indeed, it has been a grand challenge to translate the superb properties of carbon nanotubes at nanoscale to macroscale. Our research findings shed light on a viable approach to addressing this challenge and achieving carbon nanotube paper that is both strong and tough."

The findings were published in a recent edition of the journal Proceedings of the National Academy of Sciences.