Nanodiamond

What is nanodiamond?

Graphical Image of nanodiamond
Nanodiamond structure and surface chemistry
TEM Image of Nanodiamonds

Nanodiamonds are one of the most advanced carbon materials in the world.
Diamonds are renowned for their superlative physical qualities such as the highest hardness on earth, superior thermal conductivity to any bulk material, and the high refractive index and abbe number. Nanodiamonds are not only small-sized diamonds with the above features but they also could generate other functions owing to their nano size, various functional groups, high dispersibility, ζ potential, and amorphous carbon.

The structure of nanodiamonds consists of a diamond core and amorphous carbon layers. In more complex terms, each particle of nanodiamonds has sp3 bonded carbon atoms covered by sp2. The most unique feature of nanodiamonds is the existence of various oxygenic functional groups on the surface, thus nanodiamonds have ζ potential in water.
The ζ potential disperses nanodiamonds uniformly and stably in water. Daicel also achieved dispersal of nanodiamonds in various organic solvents such as IPA, THF, MIBK, and Toluene by modifying surface chemicals on nanodiamonds.

Nanodiamonds are produced by a detonation method and the diamonds synthesized are extremely tiny particles with average diameter between 4~6nm.  The particles are almost spherical (precisely,  polyhedron) unlike abrasive diamonds for lapping, horning and polishing. Because of the size and the shape,  a specific surface area of a nanodiamond particle is over 300m2/g.

Nanodiamonds can be used in unique applications compared to other nano materials such as nano-silica, graphene, carbon nanotubes, fullerenes, and carbon nanohorns.
Potential applications of nanodiamonds are break-in additives for lubricants, antioxidants, grain refining agent, bio imaging, drug delivery, diamond sensors, and others. Each function of nanodiamonds in the applications is remarkably unique. 

Nanodiamonds can be a game-changing material of the future for those applications, with many products, and potential uses. 

Surface Chemistry

Nanodiamonds consist of a diamond core and amorphous carbon. Nanodiamonds have various oxygenic functional groups on the surface. Hundreds of functional groups are on the Nanodiamond surface.

ζ potential

Nanodiamonds have ζ potential in dispersions.
The ζ potential disperses Nanodiamonds uniformly and stably in water and some organic polar solvents.

ζ potential of nanodiamonds

Making Nanodiamonds

Nanodiamonds are produced from explosives by detonation method followed by purification and dispersion processes. Daicel Corporation has installed a test facility for detonation process in our Harima Plant (Hyogo, Japan). A Diamond structure is formed from carbon atoms in explosives(a mixture of TNT and RDX ) at very high temperature and pressure by detonation in a closed chamber.

Detonation Method

How to Produce nanodiamonds(Detonation Method)

Single Digit Nanodiamonds

Nanodiamonds are originally obtained as aggregates. It is expected that diamond properties will be more prominently expressed when the aggregates are further disintegrated into primary particles. Daicel is developing the single digit nanodiamond (SDND).

Size

The nanodiamond particle is remarkably small, 4~6nm.
The particle size is 20 times smaller than a virus.

Comparison of Tiny Particle Sizes

Particle Numbers

There are about 900 quadrillion particles(9×1017) in 1 carat of nanodiamonds.

1particle/carat

Particle Numbers of a diamond per 1 carat

9×1017particles/carat

Particle Numbers of nanodiamonds per 1 carat