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Atomic Force Microscopy-Based Infrared Microscopy for Chemical Nano-Imaging and Spectroscopy
Published in Cai Shen, Atomic Force Microscopy for Energy Research, 2022
When the IR radiation is broadband, the asymmetric Michelson interferometer is used analogously to a Fourier transformation spectroscopy, i.e., FTIR. The optical path of the reference arm is scanned over a distance of several centimeters while collecting the near-field signal from non-fundamental lock-in demodulation. During the collection, the lateral position of the AFM tip is fixed, and the AFM is under the tapping mode feedback. The near-field signal versus the optical path of the reference arm forms an asymmetric interferogram if the sample contains resonance. Figure 6.9a displays two interferograms from a boron nitride nanotube and a Si substrate [61]. Fourier transform of the interferogram reveals a complex spectrum with both amplitude and phase—or equivalently the real and imaginary parts of the spectrum. Figure 6.9b displays the amplitude and phase of the BNNT IR response from nano-FTIR measurement. The resonances in the sample excited by the IR field remain excited within their lifetime, causing the interferogram to exhibit asymmetric elongation. After Fourier transforms, the asymmetric interferogram leads to a presence of the imaginary component, which is extracted to represent the IR absorption due to sample resonances (Figure 6.9c). The imaginary part of the Fourier transform is equivalent to that of the regular FTIR spectrum. Because an FTIR-equivalent spectrum is collected underneath a nanoscopic AFM tip, the method is termed nano-FTIR. It has become a standard practice for s-SNOM with broadband infrared sources to acquire IR spectra.
Augmented Cylindrical Waves for Nonchiral Nanotubes and Wires
Published in Pavel N. D’yachkov, Quantum Chemistry of Nanotubes, 2019
GaAs (5, 5) is an isoelectronic and isostructural analog of the (5, 5) boron nitride nanotube (Bolshakov et al. 2018). In calculations of the band structure of this nanotube, the Ga–As distance was assumed to be equal to 2.44 Å, the interatomic distance in sphalerite-like GaAs. The full-potential integration grid contained up to 30, 64, and 30 nodes along R, Φ, and Z, respectively. The full-potential distribution was constructed for two-unit cells in each direction, because the atomic electron densities of Ga and As atoms decrease more slowly than for C, B, and N atoms. The width of the valence band is 10.6 eV; the predominantly s band of width 2.7 eV is separated from the predominantly p part of the valence band by a gap of 4.5 eV (Fig. 1.36).
Piezoelectrical Materials for Biomedical Applications
Published in Jince Thomas, Sabu Thomas, Nandakumar Kalarikkal, Jiya Jose, Nanoparticles in Polymer Systems for Biomedical Applications, 2019
M. S. Neelakandan, V. K. Yadu Nath, Bilahari Aryat, K. A. Vishnu, Jiya Jose, Nandakumar Kalarikkal, Sabu Thomas
Boron nitride nanotube (BNNT) is a critical intrigue to established researchers in view of their imperative properties perfect for basic and electronic applications. They are structurally similar to the carbon nanotube. Alternating B and N atoms entirely substitute for C atoms in a graphite-like sheet with almost no change in atomic spacing. However, despite this similarity, carbon and BNNTs exhibit many different properties. Our investigations of the cytocompatibility of BNNTs with human neuroblastoma cells exhibit that their cell uptake does not affect suitability, metabolism, and replication of this cell line. While having a high Young modulus like CNTs, BNNTs have thermal stability and have magnificent piezoelectric properties, better than those of piezoelectric polymers. Whereas many applications of CNTs in the field of biomedical technology have been proposed in the past few years, the translation of BNNTs for use in this field has been largely unexplored. One reason for this stems from the high chemical stability of BNNTs, which accounts for their poor dispersibility in the aqueous solvents required for biological applications. This problem has been recently resolved using a technique of noncovalent polymeric wrapping that allows aqueous dispersion of BNNTs and hence biocompatibility, enabling studies on their interaction with and effects on living cells. Moreover, fluorescent labelling of BNNTs with quantum dots enables us to track the cellular uptake and internalization of polymer-wrapped BNNTs via the endocytosis pathway.74
The application of nanogenerators and piezoelectricity in osteogenesis
Published in Science and Technology of Advanced Materials, 2019
Fu-Cheng Kao, Ping-Yeh Chiu, Tsung-Ting Tsai, Zong-Hong Lin
Boron nitride nanotubes (BNNTs) have shown great potential for practical use in many areas due to their excellent intrinsic properties, including superior mechanical strength, high thermal conductivity, electrically insulating behavior, piezoelectric property, neutron shielding capability, and oxidation resistance [90]. The piezoelectric property of BNNT is superior to that of piezoelectric polymers, with a d33 coefficient of 0.3 pC/N [91]. Over the last few years, BNNT has gained increasing attention in the field of osteogenesis, owing to its favorable biocompatibility, large specific surface area, and superior mechanical properties [92]. BNNT composite scaffolds have been shown to have a positive influence on osteogenesis and osteoinductive properties, owing to more calcium deposition and up-regulated expression levels of osteoblast markers, as presented in the study by Shuai et al [93]. (Figure 11). Xia Li et al. also presented similar results indicating that a BNNT layer could promote the attachment and growth of mesenchymal stem cells and enhance ALP activity, a marker of osteogenic differentiation [94]. Moreover, the positive influence on cell proliferation and attachment to BNNT seems to be exclusively related to osteoblasts, but not on chondrocytes, fibroblasts, or smooth muscle cells [95]. Therefore, BNNT is potentially useful for bone regeneration and orthopedic applications.
A density functional theory outlook on the possible sensing ability of boron nitride nanotubes and their Al- and Si-doped derivatives for sulfonamide drugs
Published in Journal of Sulfur Chemistry, 2020
Zahra Rahmani, Ladan Edjlali, Esmail Vessally, Akram Hosseinian, Parvaneh Delir Kheirollahi Nezhad
Carbon nanotubes (CNTs), graphene, and carbon nanocages with promising potential as strong adsorbents to extract organic contaminants from aqueous media, due to their strong interactions, large surface area, high surface hydrophobicity and outstanding physicochemical features have been demonstrated and well documented [9–15]. The electronic properties of CNTs are dependent on their diameters and helicities. Consequently, controlling their geometrical structure and tuning their electronic properties is much more complicated. Accordingly, these geometric features cause serious restrictions for their use [16,17]. Boron nitride nanotubes (BNNTs) are structurally similar to CNTs. Significant attention has been devoted to using BNNTs since their electronic properties are independent on chirality, which makes them appropriate for chemical sensing applications [18–22]. Furthermore, the excellent thermal and chemical stability [23], cytotoxicity [24] and biocompatibility [25,26] properties of the BNNTs, as compared to the CNTs, have motivated chemists to examine their potential applications as modern tools in the biological, nanomedicine and therapeutic domains as well as their interaction with biomolecules [27–31]. The experimental and theoretical studies have indicated that the chemical doping process with special atoms made the BNNTs more sensitive and reactive toward various molecules [32–34]. For example, Wang et al. [35] have reported that Ge doped into (8,0) single-walled BNNTs improved the electronic properties of BNNTs and increased their adsorption sensitivity toward CO and NO as judged by the density of states (DOS) and electrical charge density.
Magnetic and structural properties of BNC nanotubes
Published in Molecular Physics, 2019
Mohammad Yaghobi, Ali Bahari, Mojtaba Yaghobi
Boron nitride nanotubes (BNNTs) are structurally analogous to carbon nanotubes (CNTs), but exhibit completely different physical, chemically and thermally properties. BNNTs has superior properties [11-13] Contrary to the structural similarities that CNTs has with BNNTs, it has different chemical and physical properties, including BNNTs electrical properties are not dependent on their chirality and diameter since they have a large band gap of about 5.5 eV [14]. Because BNNTs contains boron and nitrogen atoms, it has a different electronic structure and charge distribution is asymmetric in bonds compared to CNTs [15].