Amorphous helical carbon nanofibers synthesized at low temperature and their elasticity and processablity

Helical carbon nanofibers are synthesized by thermal chemical vapor deposition using copper nanocrystals as a catalyst and acetylene as a source gas at the low temperature of 195 °C. These nanocoils are symmetrically grown on copper nanocrystals in the form of twin helices. They contain high content of hydrogen. Their molecular structures are different from polyacetylene. They can be classified as a new type of amorphous carbon nanofibers. They present novel elasticity and interesting processability. The twin helices exhibit not only the reversible extension of the nanocoil itself but also the reversible angle change between the two nanocoils. They can be easily separated into two by electron beam heating. However, if a certain section of the nanocoil is heated by electron beam in a scanning mode, it will adjust its structures along the scanning line of the electron beam.