Scientists believe that by exploiting nature's ingenuity at the nano scale, they will soon be able to develop new green materials which will share some of the physical properties of steel.
Research by a team of scientists in the US has found that the cellulose nanocrystals which confer plants with their structural resilience possess remarkable properties which will strongly favour their usage in the development of new bio-materials.
A paper detailing the results of their research published in the December issue of Cellulose claims the use of sophisticated modelling methods has determined that cellulose nanocrystals possess all the toughness of steel.
The paper was jointly authored by Fernando L. Dri, a Purdue doctoral student; Louis G. Hector J., a researcher from General Motors’ Chemical Sciences and Material Systems Laboratory; Robert J. Moon, a researcher from the US Forest Service’s Forest Products Laboratory; and Pablo D. Zavattieri, a Purdue University assistant professor of civil engineering.
Their research involved the use of precision models of the atomic structure of cellulose in tandem with quantum mechanics to predict the physical properties of cellulose nanocrystals.
This method was necessitated by the nano scale of the crystals, the qualities of which are extremely difficult to ascertain via measurement or observation due to their incredibly small size.
Cellulose nanocrystals are typically only three nanometres in width and 500 nanometres long – roughly a thousandth the span of a grain of sand. This means they cannot be adequately observed using light microscopes as well as most other forms of scientific equipment.
The modelling method applied by the scientists found that cellulose crystals possess a stiffness of 206 gigapascals – a level which is equivalent to the strength of steel.
The discovery of this remarkable physical property has the potential to expand the gamut of applications for green bio-materials based upon plant cellulose.
Cellulose nanocrystals could be used in lieu of carbon nanotubes as a greener means of strengthening materials such as polymers and concrete.
Their sheer ubiquity in the natural world makes them a cheap and accessible base material – cellulose can be derived from a broad range of organisms, including plants, trees, algae and certain types of bacteria.
Cellulose nanocrystals also possess the added advantages of being as inherently carbon-neutral and as biodegradable as the sources from which they are derived.