Alternative eco-friendly materials that can replace metals are of high demand. The reasons behind this are many, including polluting mining processes, expensive manufacturing of products made of metals, and of course, the need of making everything lighter yet still tough and strong.
With this in mind, a group of engineers from University of Maryland, decided to explore the possibility of using the plant-based, renewable cellulose and turn it into a suitable substitute.
Cellulose was chosen because of its hydrogen bonds that link the chains. These make the produced material, on one hand, much stronger, and on the other, they give it the ever-so-wanted self-healing ability, as hydrogen bonds can reform when cellulose is broken.
The team developed super thin paper sheets out of cellulose with varying sizes of fibers- the range was from 10 nanometers (nm) to 30 micrometers. They then tested the strength of the produced paper and found that the one made of cellulose fibers of 10 nm in size (nanofibers) were 40 times tougher and 130 times stronger than regular paper with cellulose fibers of 0.01mm (10, 000nm).
The engineers explained this with the number of hydrogen bonds. The smaller the cellulose fibers, the more hydrogen bonds per square area, and therefore the stronger the material. In addition, the nanofibers reformed much faster than any other.
The team foresees big potential for their new nanopaper material. They are convinced that the lightweight, yet strong and tough, thin paper sheets can lead the way to light energy efficient vehicles. In addition, it brings researchers and engineers a lot closer to developing transparent cellulose nanopaper, which in turns could lead to the first-of-a-kind paper electronics.
The findings are published in the latest issue of the Proceedings of the National Academy of Sciences (PNAS).
Image (c) University of Maryland