Carbon nanobud
Encyclopedia
In nanotechnology, carbon
nanobuds form a material (discovered and synthesized in 2006) which combines two previously discovered allotropes of carbon
: carbon nanotube
s and spheroidal fullerene
s (or, in short, fullerenes). In this new material, fullerenes are covalently bonded
to the outer sidewalls of the underlying nanotube. Consequently, nanobuds exhibit properties of both carbon nanotubes and fullerenes. For instance, the mechanical properties and the electrical conductivity of the nanobuds are similar to those of corresponding carbon nanotubes. However, because of the higher reactivity of the attached fullerene molecules, the hybrid material can be further functionalized through known fullerene chemistry. Additionally, the attached fullerene molecules can be used as molecular anchors to prevent slipping of the nanotubes in various composite materials, thus modifying the composite’s mechanical properties.
Due to the large number of highly curved fullerene surfaces acting as electron emission sites on conductive carbon nanotubes, nanobuds possess advantageous field electron emission characteristics. Randomly oriented nanobuds have already been demonstrated to have an extremely low work function
for field electron emission. Reported test measurements show (macroscopic) field thresholds of about 0.65 V/μm, (non-functionalized single-walled carbon nanotubes have a (macroscopic) field threshold for field electron emission as high as 2 V/μm) and a much higher current density as compared with that of the corresponding pure single-walled carbon nanotubes. The electron transport properties of certain NanoBud classes have been treated theoretically. The study shows, that electrons indeed pass to the neck and bud region of the nanobud system.
Canatu Oy, a Finnish company, claims the intellectual property
rights for nanobud material, its synthesis processes, and several applications.
electronic structure suggest wide applicability of nanobuds. As the production processes are scalable, the nanobud applications may have industrial importance.
Carbon
Carbon is the chemical element with symbol C and atomic number 6. As a member of group 14 on the periodic table, it is nonmetallic and tetravalent—making four electrons available to form covalent chemical bonds...
nanobuds form a material (discovered and synthesized in 2006) which combines two previously discovered allotropes of carbon
Allotropes of carbon
This is a list of the allotropes of carbon.-Diamond:Diamond is one of the most well known allotropes of carbon. The hardness and high dispersion of light of diamond make it useful for both industrial applications and jewellery. Diamond is the hardest known natural mineral. This makes it an...
: carbon nanotube
Carbon nanotube
Carbon nanotubes are allotropes of carbon with a cylindrical nanostructure. Nanotubes have been constructed with length-to-diameter ratio of up to 132,000,000:1, significantly larger than for any other material...
s and spheroidal fullerene
Fullerene
A fullerene is any molecule composed entirely of carbon, in the form of a hollow sphere, ellipsoid, or tube. Spherical fullerenes are also called buckyballs, and they resemble the balls used in association football. Cylindrical ones are called carbon nanotubes or buckytubes...
s (or, in short, fullerenes). In this new material, fullerenes are covalently bonded
Covalent bond
A covalent bond is a form of chemical bonding that is characterized by the sharing of pairs of electrons between atoms. The stable balance of attractive and repulsive forces between atoms when they share electrons is known as covalent bonding....
to the outer sidewalls of the underlying nanotube. Consequently, nanobuds exhibit properties of both carbon nanotubes and fullerenes. For instance, the mechanical properties and the electrical conductivity of the nanobuds are similar to those of corresponding carbon nanotubes. However, because of the higher reactivity of the attached fullerene molecules, the hybrid material can be further functionalized through known fullerene chemistry. Additionally, the attached fullerene molecules can be used as molecular anchors to prevent slipping of the nanotubes in various composite materials, thus modifying the composite’s mechanical properties.
Due to the large number of highly curved fullerene surfaces acting as electron emission sites on conductive carbon nanotubes, nanobuds possess advantageous field electron emission characteristics. Randomly oriented nanobuds have already been demonstrated to have an extremely low work function
Work function
In solid-state physics, the work function is the minimum energy needed to remove an electron from a solid to a point immediately outside the solid surface...
for field electron emission. Reported test measurements show (macroscopic) field thresholds of about 0.65 V/μm, (non-functionalized single-walled carbon nanotubes have a (macroscopic) field threshold for field electron emission as high as 2 V/μm) and a much higher current density as compared with that of the corresponding pure single-walled carbon nanotubes. The electron transport properties of certain NanoBud classes have been treated theoretically. The study shows, that electrons indeed pass to the neck and bud region of the nanobud system.
Canatu Oy, a Finnish company, claims the intellectual property
Intellectual property
Intellectual property is a term referring to a number of distinct types of creations of the mind for which a set of exclusive rights are recognized—and the corresponding fields of law...
rights for nanobud material, its synthesis processes, and several applications.
Practical applications
Properties such as chemical reactivity, good dispersion and variable band gapBand gap
In solid state physics, a band gap, also called an energy gap or bandgap, is an energy range in a solid where no electron states can exist. In graphs of the electronic band structure of solids, the band gap generally refers to the energy difference between the top of the valence band and the...
electronic structure suggest wide applicability of nanobuds. As the production processes are scalable, the nanobud applications may have industrial importance.