International researchers led by distinguished professors from the UNIST Institute of Basic Science (IBS) Center for Multidimensional Carbon Materials (CMCM) have synthesized a new material composed of densely packed diamond-like carbon nanofibers.
As stated in a recent article in the journal ("Synthesis of Diamond-Like Carbon Nanofiber Film"), the researchers pointed out that this new carbon material has a high concentration of tetravalent bonded carbon (diamond-like nanofiber There are many C atoms with 4 other atoms bonded; this is also called "sp3 bonded carbon".
The researcher said: "Diamond-like carbon nanofiber film is synthesized by heating copper nanoparticles with a diameter of a few nanometers on a substrate in acetylene and hydrogen." The synthetic fiber is very dense and forms a thin film. These tightly packed nanofibers can also be separated into powder form, which may expand its application range. "
In this study, the research team was able to determine the parameters that affect the packing density of nanofibers, namely the hydrogen concentration and the size of the copper nanoparticle catalyst. By adjusting these parameters, the bulk density can be significantly increased, resulting in the formation of curved films.
Field emission scanning electron microscope images of copper nanoparticles and synthetic diamond-like carbon fiber films, and high-resolution transmission electron microscope images of single nanofibers
The X-ray photoelectron spectroscopy, solid-state nuclear magnetic resonance, elemental analysis and Raman spectroscopy of the elemental composition and chemical bond structure in these diamond-like nanofibers found that sp3 is bonded to carbon atoms (sp3: sp2 approximately 2 carbon atoms Proportion is dominant (sp2-bonded C atoms are connected to 3 other atoms instead of 4 atoms (such as in graphene and graphite), and in diamond, all C atoms are "sp3 bonded" ). Use Raman spectroscopy and elemental analysis to determine the hydrogen content in the nanofibers of about 25-50 atomic %.
"Due to its high sp3-carbon content, this material is different from other vapor-grown carbon nanofibers, including nanotubes composed mainly of stacked graphene layers and carbon nanocoils with an sp3:sp2 carbon ratio of approximately 0.25," The researcher explained.
Resistivity (1.2±0.1×10 6 Ω cm-which is electrically insulating), density (2.5±0.2 g cm-3; the density of diamond is 3.5 g cm-3), surface area (28±0.7 m 2 g-1 ), chemically inert and wettability to various liquids. These properties are similar or "better" to most of the reported diamond-like carbon films, but the mechanical properties of this diamond-like carbon nanofiber film are found to be completely different from the conventional continuous diamond-like carbon film because it is made of nanofibers.
The researchers said: "We have discovered a new form of carbon, and people may hope that our work can inspire others to follow this research path to further research." "Among other things, we are also engaged in new carbon materials. We are interested in obtaining the final pure diamond fiber and further research on this diamond-like carbon nanofiber."