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ITC’s Olga A. Shenderova: Exploring the Cutting Edge of Nanodiamonds

by Editor1 last modified August 01, 2007 - 16:19

Dr. Olga A. Shenderova is Senior Scientist and Head of the Nanodiamond Laboratory at the International Technology Center in Raleigh, North Carolina. Her passion for nanodiamonds is reflected in her work, where she and her colleagues have developed a cleaner and more eco-friendly ways to produce nanodiamonds for a variety of uses – sunscreens, paints, polymers and even integrated circuits. Dr. Shenderova emerged as a leading voice in nanodiamond fabrication after her research on atomistic modeling and solidified came public during the world’s first International Conference on Detonation Nanodiamonds in 2003.

ITC’s Olga A. Shenderova: Exploring the Cutting Edge of Nanodiamonds

Dr. Olga A. Shenderova is a Senior Scientist and a Head of the Nanodiamond Laboratory at the International Technology Center, Raleigh, North Carolina, a non-profit research corporation.


Nanodiamond -- ”The most intriguing crystal on Earth”

Nanodiamond is “the most intriguing crystal on Earth” and “full of surprises, she tells NanoScienceworks.org. “I never get bored with this material. Its many varied properties are fascinating. We continue to be surprised. Its optical properties were completely unanticipated, its behavior in nanocomposites and nanofluids pushed us in new directions, and its behavior in combination with other nanostructures will result in new classes of materials. … Almost every day is consumed by discussions of potential applications for this material both at work and home.”

Dr. Shenderova’s on-going fascination with nanodiamond can be understood by visiting the ITC website, where the term “nanodiamond” broadly describes a variety of diamond-based materials at the nanoscale, including pure-phase diamond films and diamond particles. Nanodiamond synthesis involves methods as diverse as gas phase nucleation at ambient pressure to high-pressure, high-temperature graphite transformation within a shock wave.

Nanodiamond Research Breakthroughs
Dr. Shenderova and her ITC research group continue to tap into rich veins of nanodiamond research and the discovery, particularly in the field of detonation nanodiamonds (DNDs).

As its name implies, “detonation nanodiamond” is diamond material that originates from a detonation. When a traditional explosive mixture of TNT/RDX (1:1), for example, is detonated (20-30 GPa, 3000° C) diamond particles with a diameter of ca. 4 nanometers are formed. But this technique can often create metal and non-diamond carbon contaminants in the nanodiamond, and therefore limit the quality or the applications for nanodiamond made in this way. Currently all manufacturers producing detonation nanodiamonds use strong liquid oxidizers to extract nanodiamonds from the detonation soot.

”After [the] explosion process, the product of the explosion, the detonation soot, contains 40-70% of nanodiamond; the rest is amorphous carbon and graphite and metal impurities (up to 5%),” Dr. Shenderova said. “Non-diamond carbon and metal impurities are oxidized/extracted by treatment of the soot in strong acids. Instead of acids, her team applies ozone treatment, she added.

So, under Dr. Shenderova’s direction, ITC and New Technologies, Russia has focused on cleaner, more efficient ways to product and retrieve detonation nanodiamond. For example, ITC and New Technologies of Russia are using ozone treatment to purify DNDs from detonation soot, which is the raw material following detonation synthesis. This treatment is an ecologically friendly “dry” method of purification as opposed to traditional methods that use hazardous liquid oxidizers. “Due to this new method of purification, the cost of DNDs may be reduced by 40%, making it more affordable for many applications. The material itself (DNDO) has superior properties in terms of dispersion in solvents as compared to DNDs purified by other methods,” Dr. Shenderova said.

Dr. Shenderova crisply describes the issues related to improving DND fabrication and reclamation is an October 2006 paper (jointly published with New Technologies of Russia researchers) entitled “Modification of Detonation Nanodiamonds by Heat Treatment in Air.” The following is from her abstract.
In order to readily utilize nanodiamond (ND) particulates produced by detonation synthesis in many nanotechnology applications, it is necessary to modify the surface chemistry and to separate the particles into a more narrow range of particle sizes. Surface fictionalization and fractionalization are highly dependent upon the method of ND synthesis and purification. For example, when material purified through the use of strong liquid oxidizers is used to produce hydrosols, they are unstable and difficult to fractionalize. In this study we developed a method of preparation that overcomes these two barriers. ND powder previously purified with a mixture of sulfuric acid and chromic anhydride was treated as follows: annealed in air followed by dispersion in water using a high power sonicator and multi-step ultracentrifugation. This treatment resulted in stable hydrosols formed from the smallest particle-size fractions.
Onion-like carbon (OLC) has also been a fruitful area of research. ITC, Vladimir Kuznetsov at the Boreskov Institute of Catalysis in Russia, and partners funded by the NATO Science for Peace program have demonstrated that OLC is an efficient absorber of a broad-band of radiation extending from the microwave to the terahertz region of the spectrum.

From Lab to Commercialization
Although ITC often sells DNDs to groups who want to utilize them in their research, industrial customers require more uniform and more predictable properties. As a result of this, a significant portion of ITC’s research has centered on developing a better understanding of the role material synthesis, material properties, and surface functionalization play in the eventual application. Dr. Shenderova shares an exciting prospect: “In 2007, together with New Technologies, we are planning to launch DNDO of ozone purification on the market. This unique product does not have world analogies. The material will be available in kilogram quantities in early 2008. Development of the reactor for DNDO processing was supported in part by the US CRDF program (First Steps to Market in collaboration with Rivis, USA, a sister corporation of ITC).”

Making DND a “Material of Choice” for More Applications
Dr. Shenderova is fast becoming an expert at the commercialization of DNDs. Obtaining a US patent for this along the way, she and Gary McGuire demonstrated the improved temperature of thermal degradation, adhesion, and thermal conductivity for DND-based polymer composites that are intended for use as interlevel dielectrics in integrated circuits where a high thermal budget is a concern.

Applications of DNDs in sunscreens, paints, and polymers to provide UV protection or to avoid UV degradation of the material or underlying surface are also under development (patent pending). “Importantly for sunscreen applications, it was shown that DND is nontoxic and biocompatible. At certain particle sizes and loading, transparency in the visible region of the spectrum is preserved in formulations and coatings,” explains Dr. Shenderova. Another patent pending is the application of OLC as a radar-absorbing material.

Dr. Shenderova would to like to continue commercializing DND and reducing its price: “Currently, DND is produced in tons and, in principle, can be cheaper than $1/gram. While it is not very popular in the United States, several groups in the United States, including ours, are working to make it the material of choice for a variety of applications.”

Dr. Shenderova says she is “enjoying learning to be an entrepreneur, especially when it comes to broadening the appeal for DNDs. “Soon we will provide DND powder that will disperse well in both organic solvents and water as a powder… . This will simplify shipping and handling of the material. We have a growing portfolio of patents on DND applications and, for most, we are seeking partners to commercialize them… . It is challenging to develop large-scale production methods for OLC but we are well along the path to achieving this status. Having the large capacity to produce high-quality material to meet customer’s demands will fill a demand that already exists.”

Dr. Olga A. Shenderova is a Senior Scientist and Head of the Nanodiamond Laboratory at the International Technology Center, Raleigh, North Carolina, USA, a nonprofit research corporation (see http://www.itc-inc.org/nanodiamond.html). She currently works on the modification and fractionation of nanodiamond (ND) particles, the development of ND-polymer composites, optical properties of ND and related materials, and biological-related applications of ND. Previously, during her appointment at North Carolina State University, Dr. Shenderova performed atomistic simulations of mechanical and electronic properties of carbon nanostructures. She received her Ph.D. in Computational Materials Science from St. Petersburg State Technical University, Russia. Dr. Shenderova has published more than eighty papers in peer-reviewed journals, authored more than ten book chapters, and edited two books on ND. In addition, she has authored eight US patents and patent applications related to ND.