This Small Business Technology Transfer (STTR) Phase I project focuses on the growth of high quality Boron Nitride Nanotubes (BNNTs). BNNTs have both high thermal conductance that is an order of magnitude higher than aluminum, and also have an electronic bandgap of about 6 eV that makes them an excellent electrical insulator. These unique properties promise many exciting applications. Unfortunately, BNNTs are notoriously difficult to grow, which means that they cannot be produced in the quantities necessary to fulfill industrial needs. The objective of this project is to further advance a recently developed growth technique for high quality BNNTs. If successful, this will allow for a thousand-fold increase in the BNNT growth rate over the standard chemical vapor deposition growth methodology. Furthermore, the grown BNNTs will be used to create composite materials, which will be tested for use as thermally conductive materials in thermal management of electronic systems.
The broader impact/commercial potential of this project stems from the successful increase in the growth rate of high quality BNNTs. Heat management of electronic systems is one of the most pressing challenges facing the industry. Most electronics systems use plastic materials both as mounting material and as packaging to electrically isolate the electronic components. However, these materials cause heat bottlenecks that require expensive workarounds and bulky cooling systems. For this reason, a large amount of industrial research is focused on solving these heat management challenges. When the growth rate of BNNTs has been successfully scaled up, and the feasibility of the BNNT composites are established, it will allow for wide scale production of thermally conductive, electrically insulating plastic composite materials. These materials can be used in everything from electric engine controllers to high-efficiency light emitting diode units to alleviate the buildup of heat in electronic systems. Widespread use of BNNT composites will allow for decreased electronic component failure rates, decreased need for bulky cooling systems, etc. In addition, these composites will open up the door for new innovations, such as three-dimensional electronic system architectures.
" Nano Innovations worked with researchers at Michigan Technological University to explore the industrial production potential of a technology developed at the university. The work undertaken during the grant period focused on the development of this technology, which funded a first proof of concept demonstration for industrial scale production of boron nitride nanotubes (BNNTs). The grant also funded the incorporation of these boron nitride nanomaterials into thermoset plastic composites. The intellectual merit of this project centers on the difficulty in producing large quantities of high quality BNNTs. Although this material was first synthesized in the 1990s it has been cost prohibitive to produce high quality BNNTs in quantities larger than a few milligrams. This is unfortunate, because BNNTs have a unique combination of properties in that they are both electrically insulating and extremely heat conductive. During the course of the grant period Nano Innovations and Michigan Technological University were able to increase production yield by 25,000%, which reduced the production cost of this unique material by >99%. The technique used to achieve this increase in production yield produces BNNTs that are approximately 50 micrometers long, not stained with boron particle contaminants, and easily dispersible in liquid media. This is in contrast to recent innovations that have similarly increased production, but produce products that are tangled, and cannot be easily used in an application that requires dispersion in a liquid medium. Finally, a series of proof of concept experiments were conducted by incorporating boron nitride materials into thermoset plastic composites. The team was able to produce heat conductive plastics with a heat conductivity 5 times greater than that of the control composite while maintaining the electrically insulating properties of the plastic matrix. The broader impact of the work undertaken by this funding is derived from the unique combination of properties that boron nitride nanotubes have. The largest challenge currently facing the electronics industry is the high heat density inherent in the use of high frequency and high power electronic systems. Currently this heat is trapped in the electronic system, because the plastic needed to electrically isolate the device from the environment is a poor conductor of heat. Heat conductive plastics are available in the market. Unfortunately these polymer composites are also electrically conductive so they cannot be put into direct contact with electronic circuitry. The technology developed under this grant has provided a proof of concept that the production methodology originally devised at Michigan Technological University can be scaled up to an industrial level. This will eventually provide a readily available supply of this amazing material to industries looking to significantly increase the heat management of their electronic systems.
