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Chemical Sharpening, Shortening, and Unzipping of Boron Nitride NanotubesBoron nitride nanotubes (BNNTs), the one-dimensional member of the boron nitride nanostructure family, are generally accepted to be highly inert to oxidative treatments and can only be covalently modifi ed by highly reactive species. Conversely, it is discovered that the BNNTs can be chemically dispersed and their morphology modifi ed by a relatively mild method: simply sonicating the nanotubes in aqueous ammonia solution. The dispersed nanotubes are significantly corroded, with end-caps removed, tips sharpened, and walls thinned. The sonication treatment in aqueous ammonia solution also removes amorphous BN impurities and shortened BNNTs, resembling various oxidative treatments of carbon nanotubes. Importantly, the majority of BNNTs are at least partially longitudinally cut, or "unzipped". Entangled and freestanding BN nanoribbons (BNNRs), resulting from the unzipping, are found to be approximately 5-20 nm in width and up to a few hundred nanometers in length. This is the fi rst chemical method to obtain BNNRs from BNNT unzipping. This method is not derived from known carbon nanotube unzipping strategies, but is unique to BNNTs because the use of aqueous ammonia solutions specifi cally targets the B-N bond network. This study may pave the way for convenient processing of BNNTs, previously thought to be highly inert, toward controlling their dispersion, purity, lengths, and electronic properties.
Document ID
20140011513
Acquisition Source
Langley Research Center
Document Type
Reprint (Version printed in journal)
External Source(s)
doi:10.1002/adfm.201400599
Authors
Liao, Yunlong (National Inst. of Aerospace Hampton, VA, United States)
Chen, Zhongfang (Puerto Rico Univ. San Juan, Puerto Rico)
Connell, John W. (NASA Langley Research Center Hampton, VA, United States)
Fay, Catharine C. (NASA Langley Research Center Hampton, VA, United States)
Park, Cheol (Virginia Univ. Charlottesville, VA, United States)
Kim, Jae-Woo (National Inst. of Aerospace Hampton, VA, United States)
Lin, Yi (College of William and Mary Williamsburg, VA, United States)
Date Acquired
September 10, 2014
Publication Date
July 14, 2014
Publication Information
Publication: Journal of Advanced Functional Materials
Volume: 24
Issue: 28
Subject Category
Nonmetallic Materials
Report/Patent Number
NF1676L-19380
Funding Number(s)
WBS: WBS 694478.02.93.02.12.18.23
CONTRACT_GRANT: NNNX13AB22A
CONTRACT_GRANT: FA9550-11-1-0042
CONTRACT_GRANT: W911NF-12-1-0083
CONTRACT_GRANT: NNX10AM80H
Distribution Limits
Public
Copyright
Public Use Permitted.

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