Noticias


Prof. Chen's work on Chemical Modification of Boron Nitride Nanotubes was featured as a back cover of Advanced Functional Materials

08/13/ 2014

Thumbnail image of graphical abstractThe joint efforts by a team led by Dr. Yi Lin (National Institute of Aerospace), Dr. John W. Connell (NASA Langley Research Center) and Dr. Chen just achieved an important finding about chemical modification of boron nitride nanotubes. The paper entitled “Chemical Sharpening, Shortening, and Unzipping of Boron Nitride Nanotubes” was featured on the back cover of the July 23 issue of Advanced Functional Materials, a Wiley-VCH journal (2014 impact factor 10.439).

This work was also highlighted by NASA’s internal weekly journal for Research Division.

“In the paper, the team described their discovery of a method to disperse and chemically modify the morphology of boron nitride nanotubes (BNNTs) via sonication in aqueous ammonia solutions. While BNNTs have always been considered chemically inert, the ammonia-modified BNNTs are significantly corroded and exhibit end-cap removal, tip sharpening, wall thinning, length shortening, and longitudinal unzipping. There are many potential implications from this work, such as sorting and controlling the BNNT length, purification of BNNTs, and production of BN nanoribbons as a novel type of high aspect ratio two-dimensional material.

This effort began with Liao’s work as a visiting graduate student at the NASA Langley Research Center. Liao is currently at the NIA and his work was supported by a Department of Defense grant awarded to UPR. He recently received a National Science Foundation fellowship through the Institute of Functional Nanomaterials (IFN) at UPR.”

For more information, please refer to
http://onlinelibrary.wiley.com/doi/10.1002/adfm.201470187/abstract

Liao, Y.; Chen, Z.; Connell, J. W.; Fay, C. C.; Park, C.; Kim, J.-W.; Lin, Y. “Chemical Sharpening, Shortening, and Unzipping of Boron Nitride Nanotubes.” Adv. Func. Mater. 2014, 24 (28), 4497-4506. DOI: 10.1002/adfm.201400599.

Abstract: Boron 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 modified by highly reactive species. Conversely, we discovered that the BNNTs can be chemically dispersed and their morphology modified by a relatively mild method – simply sonicating the nanotubes in aqueous ammonia solution. The dispersed nanotubes were significantly corroded, with end-caps removed, tips sharpened, and walls thinned. The sonication treatment in aqueous ammonia solution also removed amorphous BN impurities and shortened BNNTs, resembling various oxidative treatments of carbon nanotubes. Importantly, the majority of BNNTs were at least partially longitudinally cut, or “unzipped”. Entangled and freestanding BN nanoribbons (BNNRs), resulting from the unzipping, were found to be ~ 5 – 20 nm in width and up to a few hundred nm in length. This is the first chemical method to obtain BNNRs from BNNT unzipping. This method was not derived from known carbon nanotube unzipping strategies but is unique to BNNTs because the use of aqueous ammonia solutions specifically 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.