Nanoporous membrane engineered for osmotic energy systemsS. Himmelstein | May 31, 2021
Highly selective yet durable membranes for salinity gradient power generating systems have yet to be perfected, but researchers from McGill University, Canada, report a major improvement to this key blue, or osmotic, energy building block.
Mechanical strength meets exceptional selectivity in a thin 2D nanomaterial fabricated with hexagonal boron nitride monolayers supported by silicon nitride membranes. The hybrid membrane was synthesized with a new technology, tip-controlled local breakdown, developed at the university. The method uses an atomic force microscopic tip to form a nanopore in a synthetic membrane and allows multiple pore-sensors to be combined, or combined with additional detectors, electronic circuitry or tiny micro/nanochannels. The process yields very small pores at precise positions, allowing for fabrication of multiple pores exactly where needed.
A pore-to-pore spacing of 500 nm was observed to deliver optimum membrane selectivity and overall power density. The tip-controlled local breakdown technique successfully produced an array of 20 by 20 pores on a membrane surface 40 µm² in size. The researchers say that the technology described in Nano Letters could be used to produce much larger arrays.