APPLICATIONS OF TECHNOLOGY:

• Mechanical reinforcements and composites, e.g. cell phone cases, structural elements of aircraft
• Batteries, supercapacitors
• Fuel cell components
• Transistors, biosensors
• Field emission sources
• Electronic circuits
• Scaffolds for novel chemistries
• Deep ultraviolet light emitters

ADVANTAGES:

• Excellent mechanical and thermal properties
• Unusually efficient electrical insulators
• Structurally stable and inert to most chemicals
• Uniform band gap (5.5 eV)
• High sensitivity for sensor materials
• High resistance to oxidation

ABSTRACT:

Boron nitride nanotubes (BNNTs) show great promise for their mechanical and thermal properties. Unlike carbon nanotubes, which can exhibit either metallic or semiconducting characteristics, these semiconductors have a uniform wide bandgap (~5.5 eV), and make excellent electrical insulators. In addition, they have a high resistance to oxidation and are structurally stable and inert to most chemicals, rendering them suitable for a wide range of materials or device applications. Surface modification, including functionalization with small molecules, polymers, nanoparticles and thin films, helps to fully exploit these qualities.

Alex Zettl and his colleagues at Lawrence Berkeley National Laboratory have developed a microwave-assisted plasma treatment using a hydrocarbon to modify the surface of BNNTs. In one implementation, the surface of the boron nitride nanotube has been processed to include carbon atoms. In another case, using ammonia, amine functional groups are produced at the surface of the nanotube, which renders the nanomaterial soluble in chloroform. The capacity to suspend the nanomaterials in solvents should not only enhance their purification but open up a new process for nanoscale architecture.

If the BNNT is to be used as a component in a mechanical reinforcement composite, the interface between the BNNT and the other composite materials, such as the epoxy or polymer, is critical. Adding or embedding foreign elements in the outer layers of the nanotube can transfer charge to the nanotube, changing its electronic structure and its electrical, optical, and even magnetic properties. 

Once the chemical functionalization of the surface of the BNNTs has been achieved, the invention allows for the self-assembly of nanocrystals, for example gold nanoparticles, on the surface. This can help to prepare highly functionalized BNNTs that can be used as nanoscale templates for assembly and integration with a wide range of other nanoscale materials. Potential applications include use in electronic devices as interconnects, waveguides, inductors, capacitors, and transistors; heat sinks, electrostatic discharge materials and insulating architectures within electronic circuitry; integration with polymers for novel composite materials; coatings and shieldings to modify the physical, electronic, or chemical properties of other materials; novel materials that facilitate the storage of gas molecules; and novel sensor materials. 

STATUS:

• Patent pending. Available for licensing or collaborative research.

To learn more about licensing a technology from LBNL see http://www.lbl.gov/Tech-Transfer/licensing/index.html.

FOR MORE INFORMATION:

Ikuno, T., Sainsbury,T., Okawa, D., Frechet, J.M.J., Zettl, A., "Amine-Functionalized Boron Nitride Nanotubes," Solid State Communication, 2007, 142: 643-646.

Ikuno, T., Sainsbury,T., Okawa, D., Pacil, D., Frechet, J.M.J., Zettl, A., "Self-Assembly of Gold Nanoparticles at the Surface of Amine- and Thiol-Functionalized Boron Nitride Nanotubes," J. Phys. Chem., 2007.

REFERENCE NUMBER: IB-2331 and IB-2332

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