The concentration of multi-walled carbon nanotubes (MWNTs) and metal nanoparticles can be easily varied within the shaped carbonaceous solid. Carbon nanotube containing fibers and films have also been formulated from the precursor compositions. The potential range of applications is huge, including structure, energy, sensors, separation/filtration, battery, electronic displays, and nanoelectronic devices.
Using this method, carbon nanotubes (CNTs) are formed in a bulk carbonaceous solid from thermal decomposition of melt-processable precursor compositions formulated from organometallic compounds or metal salts in the presence of an excess amount of selected highly aromatic compounds.
The CNTs obtained by this patented method are not formed from gaseous components, as is common with the current CNT production based on chemical vapor deposition (CVD) methods, but rather evolve from metal and carbon nanoparticles that form within the carbonaceous solid during the carbonization process above 500°C. Only a small amount of the organometallic compound or metal salt is needed to achieve the formation of CNTs in high yield, but large quantities of the metal source can be used, depending on the application, if desired.
The solid-state method enables the large-scale production of MWNTs in moldable solid forms, films, and fibers using low-cost precursors and equipment, thereby reducing economic barriers that are inherent with carbon nanotube materials produced by more conventional methods, such as CVD. Following carbonization, the shaped carbon solids are composed of varying amounts of nanotubes and amorphous carbon, depending on such synthetic parameters as the metal catalyst concentration, carbonization temperature, and the specific organic precursors used. The amorphous carbon phase is readily removed via selective combustion at temperatures from 300–500 °C, producing highly porous, purified CNT solids with specific surface areas up to 500 m2 g-1. This highly flexible synthetic method also offers the ability to incorporate heteroatoms, for example nitrogen, oxygen, and/or boron, into the carbon nanotube solid via the initial carbon precursors.
The NRL scientists use standard resin melt processing techniques to produce various shaped CNT-containing carbonaceous configurations. Their research is the first example of using high temperature thermosetting resins as a carbon source for the formation of CNTs. Any commercially available resins, including phthalonitriles resins, polyimides, epoxy resins, phenolics, and petroleum pitches, that have good thermal properties and show superior structural integrity, are attractive sources of carbon for CNT formation by the novel method.
The use of commercially available resins is a potentially inexpensive route to CNTs. Using this simple, potentially cost-effective method could result in the production of CNTs in large quantities and various shapes. Scientists are evaluating them for possible use in numerous aerospace, marine, and electronic applications.
Donna McKinney | EurekAlert!
127-year-old physics problem solved
22.08.2019 | Norwegian University of Science and Technology
Physicists create world's smallest engine
22.08.2019 | Trinity College Dublin
Theoretical physicists at Trinity College Dublin are among an international collaboration that has built the world's smallest engine - which, as a single calcium ion, is approximately ten billion times smaller than a car engine.
Work performed by Professor John Goold's QuSys group in Trinity's School of Physics describes the science behind this tiny motor.
Together with the University of Innsbruck, the ETH Zurich and Interactive Fully Electrical Vehicles SRL, Infineon Austria is researching specific questions on the commercial use of quantum computers. With new innovations in design and manufacturing, the partners from universities and industry want to develop affordable components for quantum computers.
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Soft robots have a distinct advantage over their rigid forebears: they can adapt to complex environments, handle fragile objects and interact safely with humans. Made from silicone, rubber or other stretchable polymers, they are ideal for use in rehabilitation exoskeletons and robotic clothing. Soft bio-inspired robots could one day be deployed to explore remote or dangerous environments.
Most soft robots are actuated by rigid, noisy pumps that push fluids into the machines' moving parts. Because they are connected to these bulky pumps by tubes,...
Researchers at TU Graz are working together with European partners on new possibilities of measuring vehicle emissions.
Today, air pollution is one of the biggest challenges facing European cities. As part of the Horizon 2020 research project CARES (City Air Remote Emission...
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