Carbon Nanoparticles

Our focus on sustainability and reducing Greenhouse Gas emissions has also taken us to the world of nanotechnology with our leading-edge plasma technology. In particular, we have developed a method of producing carbon nanoparticles, including nanodiamonds, fullerenes, and carbon onions as well using our high-temperature nanosecond-pulsed plasma system in liquid-phase media.

Nanodiamonds are carbon nanoparticles with a diameter less than 100 nm. They have a diamond core in which carbon atoms have an sp3 bonding configuration with a surface or shell in which carbon atoms have an sp2 bonding configuration. Hence, the carbon atoms at the surface or outer shell are capable of being functionalized with heteroatoms or organic functional groups. Functionalization of the outer shell affects stability and performance of the nanodiamonds in different media.. 

Molecular schematic of a nanodiamond
sp2 C atoms on surface
sp3 C atoms internally
Dried carbon nanoparticles

Production of Nanodiamonds

While there are a variety of synthesis methods for the production of nanodiamonds, the first, and still most common, method of production was discovered more than 50 years ago and produces nanodiamonds with diameters of 4-6 nm. The method involves the detonation of carbon-containing explosives in closed vessel. High temperature and pressure created during the detonation event result in nanodiamond formation. However, production of monodispersed nanodiamonds by this method is challenging because detonation nanodiamonds have a tendency to strongly agglomerate. De-agglomeration requires a complicated, multi-step, expensive process.
Detonation Nanodiamond Production Facility
With our advanced plasma tools we have developed a radically new method to produce carbon nanoparticles. Our production method is simpler and much less costly vis-à-vis the detonation discharge method. In a semi-continuous operation, we pass an organic solvent between the electrodes of a version of our high-temperature, nanosecond-pulsed plasma reactor. The bulk temperature of the reactor remains close to room temperature. However, the discharge between electrodes generates a vapor bubble of the solvent which collapses rapidly to generate a shockwave with local temperature and pressure conditions optimal for nanodiamond synthesis in hydrocarbon solvent. High energy efficiency means we realize a high yield of carbon nanoparticles.
First generation simple liquid-phase reactor for production of carbon nanoparticles
Dispersions of the monodispersed carbon nanoparticles are very stable in the hydrocarbon solvent. The surfaces of produced particles are strongly hydrophobic in nature.
First generation simple liquid-phase reactor for production of carbon nanoparticles

Characterization of our Nanodiamonds

We produce both monodispersed carbon nanoparticles and weakly agglomerating (via van der Waals interactions) carbon nanoparticles. There are essentially no heteroatoms present in our carbon nanoparticles. Separation of the monodispersed and weakly-agglomerating nanoparticles is very simple, fast and inexpensive. We have achieved a step-change reduction in the cost of production of nanodiamonds relative to detonation nanodiamonds. We anticipate that that the unique size of our nanodiamonds and the cost structure of our process will enable rapid growth in existing product markets and open new market opportunities for nanodiamonds.

Our carbon nanoparticles are comprised primarily of nanodiamonds but include a minority fraction of fullerenes and carbon onions.

Our novel process produced carbon nanoparticles with a tight size distribution between 0.5-2 nanometer range.
Nanodiamonds lattice traces in TEM micrographs
TEM micrograph showing one layer fullerenes pictures
TEM micerograph showing the presence of carbon nano-onions (multilayer-fullerenes) pictures

Transfer of Carbon Nanoparticles into Polar Solvents

With additional treatment, the surfaces of the carbon nanoparticles can be made hydrophilic and the nanoparticles can then be easily transferred into water or polar solvents. Dispersions in water and polar solvents are also very stable.
Dispersion of nanodiamonds in water
Dispersion of nanodiamonds in isopropanol

Applications of Nanodiamonds

Monodispersed nanodiamonds have significant commercial potential as they have a distinct combination of outstanding mechanical properties, heat conductivity, chemical resistance, non-cytotoxicity, biocompatibility, magneto-optical and electronic properties. The performance, lifetime, and sustainability of formulated industrial and consumer products can be significantly enhanced by the addition of very small amounts of nanodiamonds (0.01 to 0.5%). Nanoplazz’s focus on a sustainable economy has defined our early product development efforts:

  1. Advanced lubricants and nanofluids to reduce friction and wear, improve heat transfer, and increase lifetime
  2. Novel polymer matrix composites with enhanced strength-to-weight ratios, thermal characteristics, and lifetimes
  3. Renewable energy applications such as in super-capacitors, solar panels and batteries
  4. Advanced coatings for enhanced UV resistance and smart optical monitoring