A film made of carbon nanotubes, developed by a group of Chinese scientists, has super-strength, ahead of (for example) Kevlar, and promises great prospects for many branches of practical application at once.
Carbon nanotubes are extremely strong and elastic. To take advantage of these properties, scientists have long been trying to make thin sheets (film) from this material, which can be used as structural coatings for cars, aerospace parts and elements, to create a protective coating for military uniforms and sports equipment. Until now, the implementation of these plans has been hampered by the difficulties in working with this category of materials. However, now scientists have found a new and rather simple way to obtain film structures based on carbon nanotubes. The first results of the conducted surveys (DOI: 10.1021/acs.nanolett.5b03863) showed that the obtained material is five times stronger than previously available developments in this segment. The resulting films are stronger than Kevlar and "regular" carbon fibers.
The structure of the new film is densely packed nanotubes, almost all of which are parallel to each other. This circumstance gives the final material enormous strength.
- Professor Jian Nong Wang from the Institute of Mechanical and Power Engineering at the East China University of Science and Technology commented on the development.
It should be noted that many groups of scientists have tried to align and structure nanotubes in a film material. As a rule, the technology of filtration and spraying a suspension of nanotubes onto the prepared surface was used for this. The peculiarities of this option consisted in the use of short nanotubes, which did not allow their structure to be well aligned in the final composition and, therefore, did not allow obtaining durable materials in the end.
Ultra-strong carbon nanotube film developed The new technology that has been successful is similar to glassblowing. Wang and his colleagues used a nitrogen gas stream. With his help, scientists began to introduce ethanol with a small amount of ferrocene and thiophene added as catalysts into special horizontal pipes placed in a furnace with a temperature of 1150-1130 ° C. The tube is a hollow cylinder with a diameter of 50 mm, the walls of which are covered with aligned carbon nanotubes that emerge from the other end of the Turk under the influence of an ethanol solution of nitrogen gas.
Then a specialized drum comes into play, which compresses and flattens the resulting substance into a two-layer black film based on carbon nanotubes.
An ultra-strong carbon nanotube film has been developed. The resulting films have an average strength of 9.6 gigapascals. For comparison, the strength of previous films based on this material did not exceed 2 hPa, the strength of Kevlar was 3.7, and the strength of carbon fiber was 7 hPa. The resulting film is 4 times more pliable than carbon fiber and can be stretched by 8% of its size compared to 2% for the same carbon fiber.
In addition to these advantages, Professor Wang also noted that the film obtained under his leadership also has a high electrical conductivity, which makes it potentially in demand in the production of products such as microelectronics and artificial muscles.
It should be noted that the described development has already received a number of positive comments from prominent world experts and scientists working in this field.