Refinement and Optimization of a Novel Synthesis Method to Semi-Continuously Extrude Pure, Ultra-Long Carbon Nanotubes (CNTs) for Application as RAD Hard, Light-weight Electrical Conductors and Signal Transmission Lines

Bandwidth demands are increasing for a wide variety of data communications systems and applications. Not only are these demands increasing to accommodate residential, commercial, space and defense data communication needs, but they are also increasing for the scientific community at various test centers and research institutions around the world. According to Topic 27d, “High Energy Physics (HEP) experiments require advanced electronics and systems for the recording, processing, storage, distribution, and analysis of experimental data. Additionally, per Topic 28d, “The High Luminosity LHC detectors will require ultimate performance detector mechanical support and cooling, that holds detector elements with micron precision and stability, and yet adds as close to zero mass as possible. Developments in this area could also be applicable to other high-priority programs. After discussions and email transactions with HEP experts, two ideal applications for the ultra-long carbon nanotube material proposed have become readily evident: i) lower mass, lower density, higher thermal conductivity grounding/shielding layers in low-mass, radiation-hard data transmission cables and ii) lower mass, lower density, higher thermal conductivity carbon nanotube reinforced carbon composite, fabric facing material to replace current carbon-fiber reinforced facing material as a primary cooling component in current and future HEP sensor systems. Both applications are relevant to current and future HEP experimentation needs and potentially provide significant improvements to current state-of-the-art associated with advanced materials for sensor cooling, radiation shielding and data transmission cable construction. And once the proposed synthesis process and catalyst configurations are refined and optimized for each application, the resulting material will provide increased thermal conductivity over current materials in use. The replacement of the solid aluminum shielding layer in ribbon cable prototypes with the novel material proposed will also significantly reduce the mass and density, while maintaining similar electrical conductivity, contributing to a significant increase in component and overall radiation length.Over the course of the proposed SBIR Phase 1 and planned Phase 2 project periods, two novel ultra-long carbon nanotube synthesis scenarios will be investigated and demonstrated to suit the applications of interest to DOE as summarized above. Nanomatronix and the Principal Investigator have been developing carbon nanotube synthesis, separation, deposition and alignment techniques since 2005. In order for a paradigm shift in structural and conductor materials to occur, synthesis processes capable of producing potentially limitless lengths of pure material that can be utilized in pure threads, fabrics, and mesh, for direct signal transmission line integration and composite material reinforcement, must be developed. And the candidate synthesis process should be multistaged, scalable and highly controllable such that ultra-long carbon nanotubes (> 1m) can be synthesized in reasonable timeframes. Significant research has gone into combining many short (20nm – 300nm long) carbon nanotube strands together to form ‘CNT yarn’. Unfortunately, up to 90% of the benefits of utilizing pure, continuous carbon nanotube molecules can be lost in the end-product due to the weaker interactions between the molecule walls of the short ‘yarn’ strands versus a continuous molecular run of pure carbon nanotube material. Both physical and electronic characteristics are significantly different between ‘CNT yarn’ versus pure, continuous molecular strands. Pure, continuous, ultra-long carbon nanotubes are needed in order to reap optimal industrial benefit and to reveal true benefits over current carbon fiber reinforced composites and ‘CNT yarn’ prototypes. Further and forconductor applications, the synthesis process must be able to selectively produce a high percentage of metallic carbon nanotubes. Conveniently, production costs for short strands (< 300nm) is now at an all-time low (~$2/gm for 70% single-wall as of 2016) providing further justification that production is maturing to the point that low-cost manufacturing is achievable. The next feasible step is the refinement and scale-up of ultra-long carbon nanotube production as proposed hereinHigh speed, low-mass shielding layers in EMI/EMF immune RAD-hard data transmission cables for scientific research and defense-based data comm. needs. Alternate, game changingapplications such as CNT-reinforced composites, CNT-reinforced fabrics and textiles, etc. are also potential outcomes of the proposed R&D.