Boron nitride nanotubes was onerous to process, in keeping with Rice University researchers. Not anymore.

A Rice staff led by professors Matteo Pasquali and Angel Martí has simplified dealing with of the extremely beneficial nanotubes to make them extra appropriate for large-scale functions, together with aerospace, electronics and energy-efficient supplies.

The researchers reported in Nature Communications that boron nitride nanotubes, aka BNNTs, assemble themselves into liquid crystals below the appropriate situations, primarily concentrations above 170 components per million by weight in chlorosulfonic acid.

These liquid crystals encompass aligned BNNTs which can be far simpler to process than the tangled nanotubes that normally type in answer. The lab proceeded to type fibers and movies from the liquid crystalline options.

“BNNT fibers are attractive for the manufacture of a variety of products, with applications that range from wearables to aerospace vehicles,” stated Martí, whose lab designed options and helped characterize the fibers produced in Pasquali’s lab.

Boron nitride nanotubes are like carbon nanotubes, however with alternating boron and nitrogen atoms as an alternative of carbon of their hexagonal lattices. Both forms of nanotubes are robust, however in contrast to electrically conductive carbon nanotubes, BNNTs are good electrical insulators and are thermally and chemically stable in air as much as 900 levels Celsius (1,652 levels Fahrenheit).

To type liquid crystals, the researchers wanted to make certain their nanotubes have been freed from contaminants. Unfortunately, these contaminants have been largely bits of boron nitride that threatened to gum up the works.

“Early BNNT samples contained lots of non-nanotube boron nitride structures,” stated graduate pupil and lead creator Cedric Ginestra. “They have been both chemically certain to the BNNTs or simply bodily adhered in a manner that prevented BNNTs from dispersing in acid and aligning at increased concentrations.

“It is difficult to separate these boron nitride allotropes from BNNTs, and hard to even measure their concentration,” he stated. “All the different types of boron nitride appear identical by basically every quantitative technique that we’ve tried so far.”

Working with their provider to optimize their BNNT purification process for the formation of liquid crystalline options and utilizing a purification process developed within the Pasquali lab helped them acquire higher batches of BNNTs, he stated. Once appropriate materials was produced, the Pasquali group was primed to shortly adapt its wet-spinning strategies for carbon nanotube fibers to make the first boron nitride threads with the process.

“There are reports of others taking solid puffs of BNNTs and stretching and twisting them to make a yarn, but that’s very different from our process,” Ginestra stated. “Our goal was to make a very highly aligned fiber because the properties are better along the length of the nanotubes.”

Liquid crystals are the best precursor for fibers as a result of the nanotubes inside are already aligned, he stated. BNNT alignment within the liquid crystals was recognized microscopically by their birefringence, a phenomenon by which crystals break up mild, prism-like, even when they look like clear.

The movies additionally demonstrated how BNNT answer processing can undertake strategies developed for carbon nanotubes, Ginestra stated. Such clear skinny movies could possibly be helpful in next-generation electronics. “The BNNT film and fiber properties will improve as the material and our understanding of the liquid crystalline solution improves,” he stated.

Martí famous BNNT movies can be helpful as filters for ultraviolet mild, antifouling coatings and for corrosion safety.

Co-authors of the paper are Rice graduate college students Cecilia Martínez-Jiménez and Oliver Dewey, alumni Ashleigh Smith McWilliams, Robert Headrick and Dmitry Kosynkin and postdoctoral researcher Jesus Acapulco; graduate pupil Asia Matatyaho Ya’akobiand professor emeritus Yeshayahu Talmon of the Technion-Israel Institute of Technology and the Russell Berrie Nanotechnology Institute, Haifa, Israel; Lyndsey Scammell and Michael Smith of BNNT LLC, Newport News, Virginia; former Rice postdoctoral researcher Daniel Marincel, now an assistant professor on the Rose-Hulman Institute of Technology, Terre Haute, Indiana; senior researcher Cheol Park of the NASA Langley Research Center, Hampton, Virginia; and related analysis fellow Sang-Hyon Chuof the National Institute of Aerospace, Hampton, Virginia.

Martí is a professor of chemistry, bioengineering and supplies science and nanoengineering. Pasquali is the A.J. Hartsook Professor of Chemical and Biomolecular Engineering, a professor of chemistry and of supplies science and nanoengineering and director of the Carbon Hub.

The analysis was supported by the Air Force Office of Scientific Research (FA9550-18-1-0014, FA9550-19-1-7045), the Welch Foundation (C-1668), the National Council of Science and Technology (CONACyT) Mexico (710115), a NASA Space Technology Research Fellowship (NNX14AL71H), the National Science Foundation (1807737, 2108838), the Department of Energy (DE-AR0001015), the United States-Israel Binational Science Foundation (2016161) and an Office of Naval Research Small Business Innovation Research grant (N68335-19-C-0560).


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