Multiwalled Boron Nitride Nanotubes: Growth, Properties, and Applications Jiesheng Wang, Chee Huei Lee, Yoshio Bando, Dmitri Golberg and Yoke Khin Yap Abstract This chapter provides a comprehensive review on the current research status of boron nitride nanotubes (BNNTs), especially the multiwalled nanostruc- tures. Experimental and theoretical aspects of the properties, synthesis, and char- acterization of BNNTs, as well as their potential mechanical, electronic, chemical, and biological applications are compiled here. 1 Introduction Boron nitride nanotubes (BNNTs) were theoretically predicted in 1994 [1, 2] and experimentally realized in the following year [3]. As described in the previous chapter, BNNTs are structurally similar to carbon nanotubes (CNTs). Thus, BNNTs exhibit extraordinary mechanical properties like CNTs [4–6]. Despite these similarities, BNNTs are different from CNTs in other aspects. BNNTs possess nearly uniform electronic properties that are not sensitive to their diameters and chiralities [1, 2]. Theoretically, their band gaps (~5 eV) are tunable and can even be eliminated by transverse electric fields through the giant DC Stark effect [7–9]. Golberg et al. have shown that BNNTs are having high oxidation resistance [10], which was later confirmed by others [11, 12]. Recent result indicates that purified BNNTs are resist to oxidation up to 1,100°C [12]. In addition, BNNTs are predicted to have piezoelectricity [13, 14] and are applicable for room-temperature hydrogen storage [15]. Junctions of CNTs and BNNTs [16] are expected to produce itinerant ferromagnetism and spin polarization [17]. Obviously, these properties make BNNTs very attractive for innova- tive applications in various branches of science and technology. J. Wang, C.H. Lee and Y.K. Yap () Department of Physics, Michigan Technological University, 118 Fisher Hall, 1400 Townsend Drive, Houghton, MI 49931, USA e-mail: ykyap@mtu.edu Y. Bando and D. Golberg World Premier International Center for Materials Nanoarchitectonics (MANA), National Institute for Materials Science, Namiki 1-1, Tsukuba, Ibaraki 305-0044, JAPAN Y.K. Yap (ed.), B-C-N Nanotubes and Related Nanostructures, 23 DOI: 10.1007/978-1-4419-0086-9_2, © Springer Science + Business Media, LLC 2009