GOALI/COLLABORATIVE RESEARCH: NANOMANUFACTURING OF VERTICALLY ALIGNED BORON-NITRIDE-NANOTUBE MEMBRANES FOR ENERGY CONVERSION

Globally, there is untapped power equivalent to approximately 2,000 nuclear power plants that could be generated at coastal estuaries from the mixing of fresh and salt water. To date, however, there have been no economical ways to extract this clean 'blue' energy from natural salt gradients. This is largely due to the poor efficiencies and high cost of existing membrane technologies. This Grant Opportunity for Academic Research with Industry (GOALI) collaborative award supports fundamental research on a new approach to manufacturing membranes for efficient energy conversion from salinity gradients, using boron-nitride nanotubes (BNNT) as uniquely smooth, highly charged nanoscale pores. The new nanomanufacturing process enables fabrication of energy-harvesting BNNT membranes with power densities ten to 100 times greater than existing membranes, in an efficient and cost-effective manner that can be scaled up to high production rates and large-scale membranes many meter-square in size. The knowledge base and nanomanufacturing methods that are developed enable renewable energy generation from an under-utilized and non-intermittent power source, and are also generally applicable to the design and manufacture of the specialized membranes that are critical to many industrial processes. This GOALI collaborative research, between an industrial partner, Chasm Technologies, and Chemical and Mechanical Engineers at two universities, helps students develop multidisciplinary skills and gain industry-relevant experience. Concerted outreach efforts to spark interest in Science, Technology, Engineering and Mathematics among women and under-represented minority students enhances diversity and help fill US workforce needs. The GOALI collaborative research project devises the first scalable, roll-to-roll-compatible method for producing vertically aligned boron-nitride nanotube (BNNT) membranes. This is achieved with a solution-based approach that deposits and aligns oligomer-dispersed BNNTs under the influence of an external electric field, and locks the nanostructure in position by in situ polymerization. The project develops a fundamental understanding and methods for solution-based fabrication at lab scales, targeting 1-10 cm2 membranes with pore densities of 108 - 1010 BNNTs/cm2. The availability of such membranes provides answers to basic questions regarding ion and liquid transport in highly charged nanoscale pores, the implications for molecular separations and electrokinetic energy conversion. The academic collaborators are planning to work with industry partner Chasm Technologies to develop the subsystems and processing steps (e.g., coating, electrokinetic alignment, curing, and post processing) to enable roll-to-roll manufacturing of large-area BNNT membranes. Together, the team studies scalability of the manufacturing process, membrane yield and performance as the size is increased to 100 cm2 and beyond.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.