Old newspapers can be used for cheap, large scale production of carbon nanotubes

Researchers have shown that old newspapers can be used as a material on which carbon nanotubes can be grown on a large scale, an advance that may new lead to low cost, eco-friendly methods for manufacturing the tiny molecules.

The researchers, including Indian-origin researcher Varun Shenoy Gangoli from Rice University in the US, said carbon nanotubes have incredible physical properties which allow them to be used in a wide range of commercial product parts such as conductive films for touchscreen displays, flexible electronics, energy generating fabrics, and antennas for 5G networks.

The study, published in the Journal of Carbon Research, revealed that the large surface area of newspapers offered an ideal way to chemically synthesise carbon nanotubes. "Newspapers have the benefit of being used in a roll-to-roll process in a stacked form making it an ideal candidate as a low-cost stackable 2D surface to grow carbon nanotubes," said study co-author Bruce Brinson from Rice University.

The researchers, however, said not all newspapers are equally good as only those in which a china clay called kaolin is used for sizing resulted in carbon nanotube growth. "Many substances including talc, calcium carbonate, and titanium dioxide can be used in sizing in papers which act as a filler to help with their levels of absorption and wear," Gangoli said.

"However it was our observation that kaolin sizing, and not calcium carbonate sizing, showed us how the growth catalyst, which in our case was iron, is affected by the chemical nature of the substrate," he added.

The researchers said previous studies had shown that graphene - a structurally alternate arrangement of carbon atoms - carbon nanotubes, and carbon dots can be been synthesised with a variety of materials as the base including food waste, vegetation waste, animal, bird, or insect waste. But until now, they said, this research had been limited.

"With our new research, we have found a continuous flow system that dramatically reduces the cost of both substrate and post synthesis process which could impact on the future mass manufacture of single walled carbon nanotubes," said Andrew Barron, a professor at Rice University.