Nanofiber carbon materials and their modified versions were synthesized by the oxidation method at Novosibirsk State Technical University (NETI). Synthesized materials can be used in various fields — as supercapacitor in electronic devices, materials for chemoresistive* gas sensors,and fillers of polymer composites. Scientists at NSTU-NETI have patented a method for processing carbon nanomaterials.
"There are two classes of carbon nanomaterials: nanofiber carbon (nanofibers, nanotubes) and graphite-like. Work on obtaining them was carried out in the 1990s of the last century. They attempted to oxidize these materials and found that such an effect has a qualitative effect on their properties. This was the end of the research, but it was resumed after some time, when new methods of analyzing the structure and properties of materials and, new ways of modification appeared. The use of solutions was abandoned, and a gas or plasma oxidation medium was used. We started attempting to oxidize carbon nanomaterials with acid solutions of various concentrations and concluded that this method is much simpler, cheaper, and more economical than the above methods. The main parameters that affect the results are the temperature of the process and the concentration of acid. The synthesis itself is quite simple: A sample of the material is taken, filled with a volume of acid at a certain concentration, and aged for a certain time. The novelty lies in our use of solutions that have not been used before. The newest method is treatment in a solution of chromic acids. There have been no such studies, and we are the first to do this. We also use acid concentrations that have not been studied at all or have been studied insignificantly," said Valery Golovakhin, a junior researcher at the Laboratory of Chemical Technology of Functional Materials at NSTU-NETI.
Carbon materials have unique properties. These include electrical conductivity, magnetic properties, and sensory characteristics — the ability to adsorb toxic gases and use adsorption to send an electronic signal that the gas concentration has been exceeded.
According to Valery Golovakhin, carbon materials have a several applications. They are used as materials for chemoresistance gas sensors and, as electrode materials in supercapacitor. Their use as additives to other materials is popular — inorganic (metals, ceramics, etc.) and organic (polymers). Therefore, in 3D printing, carbon nanomaterials are added to polypropylene to make it more durable and flexible compared to analogues without such additives. At hydroelectric power plants, biofouling can be prevented due to a coating that contains a small admixture of carbon nanofibers: a special polymer varnish is applied in several layers, in which there is an addition of carbon, and this increases the strength of the dam itself; its destruction from friction and pressure is reduced because the additional layer is thin but solid. Bioorganisms do not grow on this coating, because such a composition of varnish with carbon nanofibers is poisonous to them.
In addition to carbon production and modification, the possibility of creating composites from various carbon materials — modified and unmodified - is being studied. Scientists are also conducting research on various combinations of carbon nanomaterials and studying their complex properties.
*A chemoresistance material is a material that changes its electrical resistance under the influence of external chemicals or gasses.