Old newspapers can be used to grow carbon nanotubes

Old newspapers can be used as a low cost, eco-friendly material to grow single-walled carbon nanotubes on a large scale, says a study.

Carbon nanotubes are tiny molecules with incredible physical properties that can be used in a huge range of things, such as conductive films for touchscreen displays, flexible electronics, fabrics that create energy and antennas for 5G networks.

"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 lead researcher Bruce Brinson from the Rice University in the US.

However, not all newspaper is equally good - only newspaper produced with sizing made from kaolin, which is china clay, resulted in carbon nanotube growth, said the researchers.

The study, published in the Journal of Carbon Research, details the research experiments carried out in producing carbon nanotubes which could have the potential to solve some of the problems associated with their large scale production such as, the high cost of preparing a suitable surface for chemical growth and the difficulties in scaling up the process.

The research team discovered that the large surface area of newspapers provided an unlikely but ideal way to chemically grow carbon nanotubes.

While there have been previous research that shows that graphene, carbon nanotubes and carbon dots can be been synthesised on a variety of materials, such as food waste, vegetation waste, animal, bird or insect waste and chemically grown on natural materials, to date, this research has been limited, according to the researchers.

"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, Professor at Rice University.

"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," said Indian-origin researcher and study co-author Varun Shenoy Gangoli.

"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," Gangoli added.

The study revealed that the large surface area of newspapers offered an ideal way to chemically synthesise carbon nanotubes.