Understanding the Nanoscale Inhomogeneity in Commercial Detonation Nanodiamonds via Advanced Material Characterization
Technical Report,01 Jan 2018,31 Dec 2019
CCDC Army Research Laboratory Aberdeen Proving Ground United States
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Detonation nanodiamonds DNDs have been widely used for many applications across different disciplines. As part of an ongoing effort that previously demonstrated variations in the structural stability of different DND samples, this work performed in-depth characterization of commercial DND samples with a special focus on identifying the nanoscale variations in the structural and chemical properties within each sample. High-resolution transmission electron microscopy and electron energy loss spectroscopy in the scanning mode were exploited to elucidate the changes in the structure with diamond-carbon core surrounded by graphitic-carbon layers during electron beam irradiation for DNDs with relatively low impurity content to demonstrate localized variations in structural instability. Although Fourier transform infrared spectroscopy and transmission electron microscopy did not indicate a significant amorphous content, powder X-ray diffraction experiments suggest distinct amorphous character and the presence of organic impurities in the relatively higher-quality diamond samples containing a higher crystallinity and lower metal and organic impurities content. The particle surface properties were also investigated with small-angle X-ray scattering, and the interfacial stability in water suspension was evaluated by zeta potential measurements. Overall, the present work highlights the importance of conducting a thorough characterization to identify the presence of contaminants that may result in unexpected results for applications using what are assumed to be a pure DND with a stable diamond structure.
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