Science and Technology 

New Materials: Nanocellulose

Eduardo Prieto 

The future lies in small things. Aware as they are that the days of the technological and productive model associated with conventional materials (plastic, silicon) are numbered, scientists are like bygone alchemists in search of the philosopher’s stone said to be capable of turning old compounds into new ones with better properties, and cheaply in large quantities. They are not looking on a visible level, but on the scale of the very small, that of ‘nanomaterials’. Graphene here takes the bow thanks to its unquestionable properties, though it is still expensive to produce. But now complementing graphene and its twin, graphane (Arquitectura Viva 140), is a new compound with unforeseen potential, nanocellulose crystal, which can be obtained from bacterial cultures or through a hydrolysis process applied to cellulose fibers of wood pulp.

The new material – a biopolymer similar to that of plastics – has properties that are in no way inferior to those of graphene. It is eight times as resistant as conventional steel besides being flexible, incredibly light, and a good conductor of electricity, so its future applications promise to be varied and surprising. First would be the mechanical uses, given that nanocellulose is made of crystals that are very hard yet very light, which is perfect for the bodywork of vehicles as well as for weapons, not to mention uses in the building industry.

Because it is conductive, nanocellulose could also have applications similar to those of graphene, replacing plastic and glass in computer screens or mobile phones, which could then become transparent and flexible. Nanocellulose can also become the raw material of nano-aerogels, extraordinarily light compounds which have the capacity to absorb as much as 10,000 times its own weight, and have superinsulation properties that theoretically make them optimal for application in the enclosures of buildings, in conventional walls as well as in glazings (see Arquitectura Viva 149).

Notwithstanding all these clear advantages, nanocellulose as a material has so far been hard to obtain, and therefore costly, although this problem could well be solved by ongoing research by the Malcolm Brown team at the University of Texas, which has managed to obtain small quantities of nanocellulose through algae that produce it spontaneously, with no need for artificially infused nutrients and therefore with reduced energy and economic costs. The thesis of Malcolm Brown is that infusing these algae with genes of Acetobacter xylinum – the common bacteria used to make vinegar – can generate large quantities of nanocellulose, and with lower production costs to boot, at least theoretically, since the raw material (the bacteria and the algae nourished by sunlight through the process of photosynthesis) abounds in nature. This would open up new possibilities not only in the development of the above-mentioned applications, but also in the use of nanocellulose as an efficient and ecological and fundamentally renewable biofuel.

There are at present only two manufacturers of nanocellulose in the world, but in a study published recently the United States government has reckoned that the new industry will by the year 2020 be moving a sum of US$600,000 million all over the globe, an astronomic amount of money. The very small will then have become extremely big.

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