Nanodiamonds old


 
NANO and DIAMOND is the winning combination.
Diamond is the most wonderful mineral in the world widely used in jewelry due to its luminescence and dispersity. Diamond has the highest hardness and thermal conductivity of any bulk material. These features determine the major industrial application of diamond in cutting and polishing tools. Outstanding properties of diamond originate from the strong covalent bonding between carbon atoms collected in cubic lattice. Each atom inside diamond structure is located in the center of the tetrahedron whose vertices are the four neighboring atoms and covalently bonded with them by sp3 hybridization. This strong and dense packing of carbon atoms define unique properties of diamond:
 
 
  • Hardness - 90–225 GPa depending on the type and crystal orientation
  • Thermal conductivity: 22 W/cmK
  • High electrical resistivity: 10¹¹ to 10¹⁸ Ωm, which is especially unique in the combination with high thermal conductivity
  • High refractive index: 2.417
  • Wide band gap {300 K}: 5.47 eV
  • Specific gravity: 3.52
  • High chemical and radiation resistance
  • Biological compatibility and non-cytotoxicity
Nanoscale diamonds have additional important features:
  • Crystallites have the average size of 4-5 nm in the diamond core and hybrid graphene like structure on the surface with variable surface chemistry
  • Surface atoms have no four covalently bonded atoms, as they have inside the crystallite, and non-paired electrons of these surface atoms cause the bonding with neighbor surface atoms by sp2 hybridization or the forming of various functional groups on the surface of crystallite.
  • Stable diamond core and chemically reactive shell enable creation of diamond composite materials with unique properties
  • The surface of nanodiamonds can be modified and adjusted for specific applications
  • Nanodiamonds with specially modified surface have high colloidal stability