recentdevelopmentofthesynthesisandengineering...

Hindawi Publishing CorporationJournal of NanomaterialsVolume 2010, Article ID 163561, 16 pagesdoi:10.1155/2010/163561

Review Article

Recent Development of the Synthesis and EngineeringApplications of One-Dimensional Boron Nitride Nanomaterials

Changhui Sun,1 Hongxiao Yu,2 Liqiang Xu,1 Qiang Ma,1, 2 and Yitai Qian1

1 School of Chemistry and Chemical Engineering, Shandong University, Jinan 250100, China2 China Tobacco Shandong Industrial Corporation, Jinan 250100, China

Correspondence should be addressed to Liqiang Xu, [email protected]

Received 5 December 2009; Revised 12 April 2010; Accepted 8 May 2010

Academic Editor: Michael Wong

Copyright © 2010 Changhui Sun et al. This is an open access article distributed under the Creative Commons Attribution License,which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

One-dimensional (1D) nanomaterials with novel photoelectric, magnetic, mechanical, and electronic transport properties havelong been the research focus throughout the world. Herein, the recent achievements in preparation of 1D boron nitridenanomaterials, including nanotubes, nanowires, nanoribbons, nanorods, and nanofibres are reviewed. As the most intriguing andresearched polymorph, boron nitride nanotubes (BNNTs) are introduced thoroughly involving their functionalization and doping.The electronics and engineering applications of 1D boron nitride nanomaterials are illustrated in nanoscale devices, hydrogenstorage, polymer composites, and newly developed biomedical fields in detail.

1. Introduction

A nanoscience and nanotechnology revolution initiated bythe observation of carbon nanotubes (CNTs) [1] has rapidlyswept the world over the last couples of decades. A numberof peculiar phenomena were found at the nanoscale. Of theepoch-making revolution, nanomaterials lie in the centralposition and construct a bridge between nanoscience andnanotechnology. Synthesis and characterization of new typesof nanomaterials have attracted enormous concentration ofscientists in chemistry, physics and materials. Of all, 1Dnanomaterials such as tubes, wires, ribbons, fibers, androds with exceptional electronic, mechanical, optical andmagnetic properties have been widely researched and usedas building blocks in nanoscale devices [2]. It is generallysuggested that quantum confinement in 1D nanostruc-tures leads to novel electronic and transport properties,which provides a good model to investigate the effect ofdimensionality and reduced size on the above propertiesof 1D nanomaterials [3]. Light-weight 1D nanomaterialswith large elastic modulus can be promising candidate inengineering field and used as reinforcement agent intocomposite materials [4].

Hexagonal boron nitride (h-BN) with layered structureanalogous to graphite is an important III-V material.

Stimulated by rapid development of carbon nanomaterials, aseries of boron nitride nanostructures have been synthesized,especially 1D nanomaterials such as nanotubes, nanowires,nanoribbons, nanofibers, and nanorods (Figure 1) [5–9].One-dimensional boron nitride nanomaterials exhibit notonly excellent thermal conductivity and high elastic mod-ulus comparable to these of carbon materials but betterthermal and chemical stability. Contrary to carbon withgood electrical conductivity, boron nitride is a nearlyelectrical insulator with a large band gap of ∼5.5 evwhich is independent of tube diameter and chirality [10].Consequently, BNNT can be used as insulating protec-tive shields encapsulating semiconducting nanowires toform nanocables [11–16]. BN nanowires and nanoribbonscould play key roles in nanoscale devices [6, 7]. And BNfibers may substitute for carbon fibers under electricalinsulating and rigorous environment at high temperature[8].

In this paper, the latest advances in synthesis andapplications of 1D boron nitride nanomaterials in device andengineering are comprehensively introduced. Of all, BNNTsand their functionalization and doping are systematicallyreviewed as well as their various applications particularly innewly developed biomedical field. Other 1D BN nanomate-rials are illustrated in detail as well.

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Figure 1: Family of 1D boron nitride nanomaterials. Scanning electron microscopy (SEM) images of (a) BN nanotubes [5], (b) BNnanowires [6], (c) BN nanoribbons [7], (d) BN nanofibers [8]. (a) Reprinted with permission of [5]. Copyright 2005 Elsevier Ltd. (b)Reprinted with permission of [6]. Copyright 2006 Institute of Physics. (c) Reprinted with permission of [7]. Copyright 2008 AmericanChemical Society. (d) Reprinted with permission of [8]. Copyright 2009 Institute of Physics.

2. Boron Nitride Nanotubes

2.1. Synthesis. BNNTs were first synthesized by Chopra et al.in a carbon-free plasma discharge between a BN-packedtungsten rod and a cooled copper electrode similar to CNTssynthesis in 1995 [17]. Following research improved thismethod by using HfB2 [18, 19] or ZrB2 [20] electrodes ina nitrogen atmosphere. Few-layer BNNTs including single-layer tubes were observed though with minor amounts(Figure 2). Most of the tube ends were closed by flat layersor encapsulated metal particles or amorphous BN material.When nitrogen-free, boron-rich electrodes incorporatingminority of nickel and cobalt were arced in a nitrogen atmo-sphere, double-walled BNNTs self-assembled into bundles orropes were mass-produced [21, 22].

BNNTs, especially single-layer ones, can be prepared bylaser ablation. BNNTs of only 1 to 3 layers with flat orpolyhedral caps were synthesized by using excimer laserablating BN target with nanosized Ni and Co powder at1200◦C [23, 24]. Low-energy electron-cyclotron resonance(ECR) plasma was also used to deposit single-walled BNNTswith fourfold and eightfold ring structures on tungstensubstrate [25]. In the absence of metal catalysts, single-wallednanotubes could also be synthesized in gram quantities using

CO2 laser ablation [26], which indicated different growthmechanism from carbon single-walled nanotubes. Arenalet al. modified this route to increase the yield of single-walledBNNTs to 80% [27]. A root-growth model was proposedbased on the observation of boron particles at the tubeends. Noticeably, Laude et al. reported similar experimentsand the products were free of single-walled nanotubes [28].These apparently controversial results suggested the poorstability of single-walled BNNTs compared with CNTs [29].However, this method was the unique route known to themassive preparation of single-layer BNNTs. Besides, Wanget al. reported high-yield synthesis of multiwalled BNNTsdeposited on Fe films coated oxidized silicon substratesadopting VLS growth mechanism using laser ablation at600◦C [30], which indicated the feasibility of laser ablationto prepare BNNTs in large scale. However, laser ablation,combined with arc-discharge, was limited owing to theexpensive and complex apparatus.

Ball milling and annealing method with facile operationand mass production was successfully introduced to thesynthesis of BN nanomaterials by Chen et al. in 1999[31]. Originally, h-BN powder was used as the startingmaterial which was ball milled and annealing at 1300◦Cunder nitrogen gas flow [31]. The product was composed of

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Figure 2: High-resolution transmission electron microscope(HRTEM) images of BNNTs prepared by arc discharge and theirtube ends [18]. (a) Six layers, (b) three layers, (c) two layers, (d) onelayer, (e–g) flat tips of tubes with different diameters, (h) disorderedtermination of a single-walled tube, (i) conical ends, (j) tube endencapsulating probably amorphous BN material. Reprinted withpermission of [18]. Copyright 1996 American Physical Society.

both cylindrical and bamboo-like nanotubes. Subsequently,elemental B powder was substituted for h-BN powderas the starting material and annealing was carried outin a nitrogen atmosphere resulting in high yield (85%)production of BNNTs including cylindrical and bamboo-likenanotubes [32–34]. However, when the annealing processwas conducted under ammonia gas flow keeping otherconditions unvaried, pure cylindrical BNNTs were obtainedwhich was attributed to two-dimensional growth of the BNphase without metal catalysis [35]. 10BN nanotubes wereprepared through substituting isotopically 10B powder for Bpowder as the starting material catalyzed by Fe particles [36].Based on systematic investigations of the nitriding gases onthe growth of BNNTs, Chen et al. proposed that ammoniagas led to 2D growth of BN (002) planes, while nitrogen gasresulted in 3D crystal growth [37]. According to this model,selective synthesis of BNNTs, bamboos and nanowires wasachieved through tuning the reaction parameters [38].BNNTs obtained by this method were generally catalyzed bymetal catalysts from the reaction vessel [39]. Besides, B2O3

can also be used as the starting material producing high-yield bamboo-like BNNTs [40]. Interestingly, over 1.0 mmBNNTs with huge resistivity could be synthesized by an

optimized ball milling and annealing method [41]. Overall,this method provides an effective mechanothermal route forthe growth of BNNTs from solid phase, which is suitable formass production of BNNTs.

In view of similar structures between CNTs and BNNTsand high reaction activity of carbon at high temperature,CNTs were utilized as the template for the growth of BNNTsdefined as carbon nanotube substitution reaction. Han et al.initiated this field by reacting B2O3 with nitrogen gas inthe presence of multishell CNTs at 1500◦C [42]. The as-obtained BNNTs were mixed phases including h-BN andrhombohedral BN (r-BN). Precise structure investigationsshowed many changes from CNTs to BNNTs, for example,decreased numbers of shells, increased orderliness of nan-otube shells along the tube axis, flat tip-end terminations,and so forth [43]. Novel conical nanotubes with their coneaxis parallel to the tube axis were regularly found in theproduct [44]. Alternatively, single-walled CNTs were usedsuccessfully leading to the formation of single-layer BNNTs[45]. In a temperature-sensitive reaction single-layer BNNTsmixed with BxC1−x and BxC1−x Ny single-walled bundleswas produced using single-walled CNTs. Existence of carbondoped BNNTs or boron and nitrogen doped CNTs indicatedthe incomplete oxidization of templates. Nevertheless, theseBxCyNz nanotubes can be further converted into BNNTsat 550◦C with an efficiency of about 60% [46]. A dramaticincrease in BNNTs yield was achieved by introducing low-sublimation-temperature metal oxides, for example, MoO3,V2O5, PbO, CuO, and Cu2O, into the reaction system asoxidization promoters [47–52]. Unique ropes of BNNTswere regularly formed containing tens of separate BNNTsvia this route. The growth mechanism was considered tobe oxidation-induced defect growth model. Aligned BNNTswere of great importance in the fabrication of nanoscaledevice which can be made interestingly via substitutionreaction using aligned multiwalled CNTs [53]. Novel hollowconical-helix BNNTs were found through additional high-temperature treatment on the basis of above method andits structure was studied in detail [54, 55]. On the whole,although this route is easily subject to carbon contamination,carbon doped BNNTs with tuned band gap which ispromising candidate in diverse photoelectrical device couldbe produced by carefully controlling the reaction parameters.

In the carbon nanotube substitution reaction, CNTsacted as both templates and reducing agent. Anothercommonly used template, porous anodic aluminum oxide(AAO), was utilized to fabrication of highly orderedBNNTs arrays. Borazine or related materials such as 2,4,6-trichloroborazine, polymeric borazine, borazine oligomerand BH3NH3 or B2H6 was generally selected as the startingmaterials [56–60]. The synthesis procedure was divided intothree steps, that is, pyrolysis of the precursors at relativelylow temperature (below 1000◦C) to produce amorphous orturbostratic or poor crystalline BNNTs, removal of AAOtemplate by immersing in 0.1 M NaOH solution or HF,and finally, not always needed, high-temperature treatmentaiming at improved crystallinity. The key factor of this routeis to choose a compatible precursor with the AAO templates.More important is that the route can also provide a facile way


to synthesize coaxial C/BN/C heterostructure by sequentialpyrolysis of acetylene and trichloroborazine over aluminatemplates [57]. C/BN/C nanotubules are essentially a nano-sized capacitor with the specific capacitance ∼100 pF/mexhibiting huge potential in microelectronics applications.Recently, a mixture of smooth boron nanowires andbranched boron nanofeather nanojunctions was employedas precursor to react with nitrogen gas forming novel boronnitride nanotube branched nanojunctions which can actas functional units in nanoelectronic and nanomechanicaldevices [61]. The results demonstrated the template role ofboron nanowires as well as reactant. Moreover, other hardtemplates may be attempted for the synthesis of BNNTs.

Actually, both the above-mentioned template methodsare performed in chemical vapor deposition (CVD) equip-ment. CVD is the widely used method for BNNTs synthesis,which usually needs catalytic growth by metal particlesfollowing typical VLS mechanism. However, available boronsource suitable for CVD synthesis is severely restricted.Frequently used gaseous boron-contained compounds in thesynthesis of boron nitride films, most notably BCl3 [62]and B2H6, can also be beneficial to the growth of BNNTs.Recently, two groups reported the massive production ofBNNTs by using B2H6-based gas precursors catalyzed by Nior Fe nanoparticles on similar substrate at low temperature(below 1000◦C) [63–65]. Volatile BN compounds, typicallyborazine or H3N·BH3, enriched the family of BNNTsprecursors. Pioneering work of CVD synthesis of BNNTs wasconducted by Lourie et al. using an in situ generated borazineas precursor on NiB or Ni2B catalysts at 1000–1100◦C [66].Recently, double-walled BNNTs with ∼2 nm diameters wereobtained from borazine with a floating nickelocene catalystat 1200◦C [67]. Tang et al. developed a new syntheticsystem based on a novel precursor composed of B2O2 andMg that was in situ generated by reacting B and MgO at1300◦C to synthesize bulk amounts of pure BNNTs in anammonia atmosphere [68]. Later on, they improved thismethod by adding FeO to the starting mixtures aiming topromote the formation of highly reactive B2O2 intermediate(Figure 3) [5]. The self-formed Fe nanoparticles catalyzedthe growth of BNNTs. Up to now, this route remainsone of the most effective carbon-free routes to BNNTsin large scale, which advanced further functionalizationand performance research of BNNTs. Subsequently, Tangattempted other metal oxides, such as, SnO, Fe2O3, GaO,and so forth [69–72]. The results showed that the combinedpromoters of MgO and FeO apparently presented thepredominant efficiency. Besides, some homemade precursorswere employed to effectively synthesize BNNTs [73]. Maet al. employed a B-N-O precursor prepared from boric acidand melamine to synthesize BNNTs under a nitrogen gasatmosphere at 1700◦C [74, 75]. Structure analysis showedthat the obtained BNNTs exhibited zigzag arrangement andrhombohedral stacking order. The nanotubes growth wassuggested to be promoted by boron oxynitride nanoclustersat the tips involving Si, Al and Ca. Subsequently, controlledsynthesis of BN nanotubes, nanobamboos, and nanocableswas implemented using the B-N-O precursor under differentconditions [76]. Ma also attempted to use NaBH4 and

NH4Cl to generate H3N·BH3 which acted as precursors toyield BNNTs by pyrolysis at 1050◦C under nitrogen gasatmosphere [77]. The as-produced nanotubes were foundto grow in a layer-by-layer fashion. In view of its successfulapplication in the mass production of CNTs, CVD techniquemay play a similar key role in the mass production of pureBNNTs in the future by selecting proper precursors andoptimizing the reaction parameters.

One facile and easy-controlled method based on con-fined reactions in a sealed autoclave developed by ourgroups has been successfully utilized to preparation of var-ious nanostructures including carbon, carbide, and nitridenanomaterials from 1D to 3D at low temperature [78–83]. The confined environment allows full diffusion andhomogeneous distribution of reactive species leading tomore efficient production and high anisotropic growth. Weproduced pure h-BN nanotubes with a maximum yield of∼50% via co-pyrolyzing NH4BF4, KBH4, and NaN3 at lowtemperature (450–600◦C) under the synergetic effect of Znand Fe powders (Figure 4) [84]. Diverse tips like acute andobtuse conical and square tips were observed in the productand many BN nanocages were found to coexist with BNNTs.The conical nanotubes with unique geometry may possessspecific properties and promising applications. The exper-imental results demonstrated the crucial role of NH4BF4

in the formation of BNNTs. Recently, straight BNNTs withdiameters ranging 30–300 nm were conveniently prepared bythe similar method using Mg(BO2)2·H2O, NH4Cl, NaN3,and Mg powder as reactants at 600◦C [85]. The BNNTs wereclosed at one ends or both ends and presented cone-liketips as well as the traditional tip-ends. Several BNNTs filledwith Mg nanorods were occasionally observed. Therefore,it was suggested that Mg powder played a catalytic rolein the formation of BNNTs. More recently, well crystallineBNNTs were synthesized as a side product together withhollow spheres [86]. The control experiments showed thatcrystalline BNNTs could be formed at quite low temperatureof 300◦C. Therefore, low temperature copyrolysis method instainless steel autoclaves has been proved to be an effectiveway for the high yield production of crystalline BNNTs.

Other methods towards BNNTs were exploited. Arcplasma jet can generate high-temperature (∼4000 K) result-ing in evaporating exposed BN sintered disk to growmultiwalled BNNTs with square tips [87]. The innermosttube with diameter of 0.6 nm was found in the product.

Based on the above discussion, synthesis of pure multi-walled BNNTs have been achieved, although single-walledand aligned BNNTs which is of significance in deviceapplications still remain a challenge. For industrial produc-tion, current methods developed in labs cannot meet therequirement yet. Moreover, precisely controlled synthesis ofBNNTs with pure hexagonal or rhombohedral stacking andzig-zag or armchair arrangement needs further research.Remarkably, commercial BNNTs are currently available fromREADE Advanced Materials, Australian National Universityand/or other companies. Although the price is still veryhigh now, this suggests huge application future of BNNTsundoubtedly. In order to fabricate devices using BNNTs,operation of BNNTs in solution via functionalization and


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Figure 3: BNNTs obtained by oxide-assisted CVD method [5]. (a) SEM image of BNNTs. (b) HRTEM image of a BNNT. Selected areaelectron diffraction (SAED) in the inset A and the fast Fourier-transform (FFT) pattern in the inset B collectively confirmed the zigzagarrangement of this nanotube layers. Reprinted with permission of [5]. Copyright 2005 Elsevier Ltd.

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Figure 4: Typical transmission electron microscope (TEM) images of BNNTs prepared at low temperature. (a) Pure and high-yield straightBNNTs bundles [84]. (b) Straight BNNTs with large diameters of hundreds of nanometers and lengths ranging from 400 nm to 5 μm [85]. (c)BNNTs jungles crystallized at 450◦C [86]. (a) Reprinted with permission of [84]. Copyright 2003 American Chemical Society. (b) Reprintedwith permission of [85]. Copyright 2007 Elsevier Ltd. (c) Reprinted with permission of [86]. Copyright 2009 Elsevier Ltd.

doped BNNTs with tuned band gap are fulfilled, which isintroduced below.

2.2. Functionalized Boron Nitride Nanotubes. Processabilityof BNNTs in solution is of great significance for thefabrication of nanodevice. In the last few years, following thesuccessful massive production of pure BNNTs, many reportsabout surface modification of BNNTs towards solubility inaqueous or organic media sprung out [88]. Functionalizationcould modulate the band gap of BNNTs in some cases.

Covalent functionalization was achieved through form-ing acylamino bond between chemical reaction of COClgroup of stearoyl chloride or chloroacetyl chloride andamino groups on the BNNTs [89, 90]. It was noteworthy thatlong alkyl chains introduced by stearoyl chloride inducedchanges in band structure of BNNTs with reduced band gap.

Another method for covalent functializaiton based on boronsite at the surface of BNNTs was established via introducingamine groups by using ammonia plasma irradiation oramine-terminated oligomeric poly(ethyleneglycol) [91, 92].Introduced alien groups at the BNNTs surface enabled faciledevelopment of composite structure on this scaffold [93].Solvothermal treatment of BNNTs in dimethyl sulfoxide(DMSO) solution caused weakened B–N bonds and chemicalpeeling of BN sheets due to cycloaddition reaction ofDMSO and BNNTs [94]. Very recently, hydroxyl groups(–OH) were successfully introduced onto the surface ofBNNTs via solvothermal treatment in hydrogen peroxide(Figure 5) [95]. X-ray photoelectron spectroscopy (XPS)studies showed that –OH groups were bonded to B sitesof BNNTs. Hydroxylated BNNTs enabled a series of furtherchemical reactions based on hydroxyl bonding.


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Figure 5: Hydroxylated BNNTs [95]. (a) A schematic diagram of hydroxylation of BNNTs. (b) Hydroxylated BNNTs (left) and pristineBNNTs (right) in water. Obviously, hydroxylated BNNTs were soluble in water forming uniform aqueous solution. Reprinted withpermission of [95]. Copyright 2009 Wiley InterScience.

BNNTs can be noncovalently functionalized byintroducing carboxylate groups from perylene-3,4,9,10-tetracarboxylic acid tetrapotassium salt (PTAS) in aqueoussolution [96]. Presumably, π-π interactions between PTASand nanotubes played a key role in this process. B-C-N/BNcoaxial nanotubes with p-type semiconducting behaviorswere then prepared from PTAS-BNNT by vacuum annealing.Polymer-wrapped BNNTs by poly[m-phenylenevinylene-co-(2,5-dioctoxy-p-phenylenevinylene)] (PmPV) perfectlydissolved in common organic media were prepared obeyingsimilar mechanism [97]. However, impurities out of BNNTspresented no interaction with PmPV. Consequently, aneffective purification method based on a conjugated polymerwrapping was established [98]. Noncovalent coating of thenanotube wall with biomoleculars such as salmon DNAand poly-L-lysine were also reported [99, 100]. Lately,stable BNNTs aqueous solution was obtained with thehelp of ammonium oleate ionic surfactants drove by weakCoulombic attraction [101]. Photoluminescence (PL)analysis showed that the intrinsic optical properties ofBNNTs were preserved.

A simplified strategy, where the boron site in BNNTswas referred to as Lewis acid, then enabling reaction withLewis bases such as trialkylamine and trialkylphosphine, wasproposed as an alternative way for soluble BNNTs [102].Unfortunately, the commonly used routes were found tobe exclusively applicable to multiwalled BNNTs. Just severalmonths earlier, soluble single-walled BNNTs in organicsolvents were obtained for the first time using quinuclidinemolecules as Lewis bases [103]. It was therefore developedto be a versatile strategy for the functionalization of bothmultiwalled and single-walled BNNTs.

Very recently, systematically theoretical study of func-tionalization of BNNTs by substituted carbenes (CR2) whereR = H, F, Cl, CH3, CN, and NO2 was conducted using densityfunctional theory [104, 105]. The electronic properties offunctionalized BNNTs by C(NO2) can be violently tunedfrom large band gap insulators to excellent semiconductors.These calculation results might be useful guide to theongoing experimental research in this field.

2.3. Doped Boron Nitride Nanotubes. Analogous to CNTscounterpart, BNNTs can be doped with other elements inthe hope of novel properties including mainly modified

band gaps. Owing to their similarity in structure, carbon-doped BNNTs were firstly and intensively studied fromboth theoretical predictions and experiments. Two typesof carbon-doped BNNTs, homogeneous B-C-N nanotubesand BN/C heterostructures, are generally considered [106–109]. The carbon nanotubes substitution reaction, AAO-templated route and covalent functionalization as discussedabove could well produce carbon-doped BNNTs [57, 96,110]. However, precise characterization of their fine struc-tures is limited by current instruments [29].

Tang et al. reported CVD synthesis of fluorine-dopedBNNTs with a doping concentration of ∼5% using BF3 asreactant [111]. Electron energy loss spectroscopy (EELS)mapping described uniform distribution of F atoms withinthe nanotubes. The current-voltage (I-V) characteristicsdemonstrated semiconducting behaviors of BNNTs afterbeing doped with highly electronegative fluorine. Severaltheoretical studies of fluorine-doped BNNTs were alsoconducted [112–114].

Si-doped bamboo-like BNNTs were synthesized viacatalyst-assisted pyrolysis of a silicon-containing polymericprecursor under N2 atmosphere [115]. Intense visible PLspectrum showed emission ranging between 500 and 800 nmpresumably contributed to Si doping. Very recently, similarstructure with Si dopant concentration of 5% was producedusing B pieces, BN powder and a piece of Si wafer asreactants (Figure 6) [116]. XPS confirmed the formation ofSi–B and Si–N bonding. The valence band analysis showedthat the band gap of BNNTs were reduced by ∼1.7 ev after Sidoping.

Apart from light elements, heavy elements dopedBNNTs were investigated theoretically and experimentally.BN nanobamboos doped with Eu were prepared throughannealing of ball milled mixture of B and Eu powder [117].Cathodoluminescence (CL) spectrum showed a new strongband emission centered at 490 nm, indicating its possibleapplication as a nanoscale visible-light source. Recently, Cu-doped BNNTs self-assembling into interesting microbeltswere synthesized using nanoscale Cu powders as catalyst[118]. The Cu doping induced a strong and red-lightemission at 695 nm in BNNTs.

Other elements, such as O, Pt, Be, Mn, and Cr [119–122]were theoretically studied to be doped into BNNTs expectingmodified transport and magnetic properties, which neededfurther experimental investigation.


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Figure 6: Si-doped BNNTs [116]. (a) SEM image of Si-doped BNNTs with worm-like (inset in (a)) or bamboo-like (b) structures. Lattice-resolved TEM image for the edges of the wall layers with its corresponding FFT ED pattern (inset in (c)) showed the (002) basal planesaligned along the tube axis with high crystallinity. EELS mapping of B, N, Si, and O atoms (d) demonstrated the homogeneous distributionof Si and the thin oxide outlayers. Reprinted with permission of [116]. Copyright 2009 American Chemical Society.

3. Boron Nitride Nanowires

Apart from nanotubes, boron nitride nanowires (BNNWs)are another important member of 1D boron nitride nanoma-terials. They can act as insulating components in nanoscaledevices. Compared with BNNTs, there are only severalreports describing the synthesis of BNNWs. Maybe due tosome aspects of BNNWs and BNNTs in common, such as,microscopic morphology and growth direction, BNNWs canbe synthesized using slightly modified routes for BNNTs.Huo et al. prepared well crystalline BNNWs through thereaction of homemade B-rich FeB nanoparticles with themixed nitrogen and ammonia at 1100◦C [123]. While usingthe same preparation procedure except for the dramaticallyreduced boron content in the FeB precursor, bamboo-likeBNNTs were obtained [124]. Recently, selective synthesisof boron nitride nanotubes, nanobamboos and plateletnanowires was implemented using a floating catalyst CVDmethod through different catalysts and reaction temperature[125]. More recently, similar selective synthesis of polycrys-talline BNNWs was achieved by annealing a stainless-steelsubstrate primarily immersed in homemade B nitrate solu-tion under the atmosphere of nitrogen and hydrogen [38].

Moreover, new synthetic systems were developed exclu-sively for BNNWs. Pure BNNWs with a uniform diameter of20 nm were prepared through deposition of boron triiodide(BI3) on a Si (100) substrate under an ammonia atmo-sphere (Figure 7) [6]. The as-obtained product possesseda disordered turbostratic structure maybe due to the lowdeposition temperature (1100◦C). Crystalline BNNWs werealso prepared by heating milled mixture of ZnO and Bpowder on stainless-steel foils under N2/H2 flow [126]. PLspectrum of the product showed a new emission band at728 nm. Presumably, it was caused by the defect-trappedstates in the BNNWs.

4. Other 1D Boron Nitride Nanomaterials

Compared with BN nanotubes and nanowires, there areonly a few reports on other 1D BN nanomaterials includingnanoribbons, nanorods and nanofibers.

In view of the importance of nanoribbons as an excellentcomponent in electric circuits and devices, BN nanoribbonsreceived extensive research from theory to experiment.Unfortunately, most of the researchs still remained the-oretic [127, 128]. The only relevant experimental reportabout BN nanoribbons was that using homemade B-N-O-Fe as precursor and ZnS nanoribbon as template hollowBN nanoribbons were obtained after evaporation of thetemplate [7]. An extraordinary ultraviolet CL emissionat 5.33 ev was found, which was promising in optoelec-tronic applications especially in ultraviolet region (Figure 8).Actually, this is not the typical model of BN nanorib-bons.

BN nanorods or, more strictly, shortened nanowires witha aspect ratio of∼100 were synthesized by nitridation of B4Cpowders in nitrogen gas on nitrate-coated Si (100) substrateat 1300◦C [9]. The crystalline nanorods presented conicalstacking along the nanorod axis. Subsequent field-emissioncharacterization showed that electrons were emitted fromboth the tips and side surface of the nanorods [129].Polyhedral BN nanorods with ordered or defective tips werealso reported [130].

As far as BN fibers are concerned, most of the meth-ods used borazine-based polymeric precursors to produceboron nitride micrometer-scale ceramic fibers [131–134],which was of striking significance in engineering appli-cations. Ma et al. synthesized crystalline BN nanofiberswith the (002) basal planes unusually perpendicular tothe fiber axis via pyrolysis of BN, B2O3 and B mixedpowders under N2 atmosphere [135]. These nanofibersexhibited a hydrogen storage capability of 2.9 wt.% under∼10 MPa at room temperature. Recently, through nitridationof B2O3-coated polyacrylonitrile (PAN) template fiberswith NH3, continuous BN nanofibers were successfullyproduced [8]. The group also synthesized aligned BNnanofibers in bulk by a more simple nitridation processof dissolved B2O3 and polyvinylbutyral (PVB) in ethanol[136]. The as-obtained BN nanofibers were crystallinewith (002) planes parallel to the fiber axis analogous toBNNTs.


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Figure 7: BNNWs synthesized from BI3 [6]. (a) A high magnification SEM image of BNNWs with uniform diameters. (b) TEM and EDpattern (inset) of BNNWs showing high purity. (c) HRTEM of a nanowire exhibiting disordered turbostratic structure. Reprinted withpermission of [6]. Copyright 2006 Institute of Physics.

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5. Device and Engineering Applications

As to device application, nanotubes and nanowires havebeen the research focus in this field due to their fascinatingelectrical, magnetic and transport properties induced bywell-known quantum confinement effects at the nanoscale.For the fabrication of devices, understanding of the elec-tronic structures of 1D BN nanomaterials can not besufficient enough. Due to the insulating nature, much effort

has been devoted to BN nanotubes and nanowires with tunedband structure from insulators to semiconductors, whichcan be defined as “bandgap engineering”. As demonstratedabove, doping with C, Si, F, and so forth, and covalentfunctionalization can lead to BNNTs with n-type or p-type semiconducting features [137]. Recently, the effects ofisotope (10B) substitution and different tube diameters onthe band gap of BNNTs were systematically studied [138,139].


In addition to excellent thermal stability below 800◦C[140], thermal conductivity and mechanical properties ofBNNTs was evaluated theoretically and measured exper-imentally. The results showed that BNNTs possess highthermal conductivity parallel to the tube axis, which isclose to that of CNTs [141]. Moreover, the axial Young’smodulus was measured up to 1.22 ± 0.24 TPa, which ismaybe the highest value of other known insulating materials[142]. These alluring performances of BNNTs endowed themwith enhanced fillers in polymer or ceramics matrix [143–146]. Previously, the boron nitride-filled polymer compositeswere fabricated using boron nitride powers rather thannanotubes as fillers aiming for high thermal conductiv-ity [147–150]. Just in the last year, Zhi et al. reportedthe fabrication of a series of BNNT-polymer compositesincluding poly(methyl methacrylate) (PMMA), polystyrene(PS), poly(vinyl butyral) (PVB), and poly(ethylene vinylalcohol) (PEVA) with high BNNT fractions up to 18–37 wt.%through a simple solution method [144]. These compositesexhibited improved performance including high thermalconductivity, low coefficient of thermal expansion (CTE)and insulating properties (Figure 9). Engineering ceramics,for example, Al2O3, Si3N4, with reinforced superplasticityby adding BNNTs was studied by the same group [145]. Itwas found that even a low addition concentration of BNNTs(0.5 wt.%) can remarkably improve the high-temperaturesuperplastic deformation of engineering ceramics. All thesefruitful explorations in the lab can undoubtedly extend theindustrial applications of BNNTs in engineering field.

Continuous BN fibers of distinctive scientific and tech-nological significance can be used as insulating fibrousreinforcements within ceramic composite in replacementof carbon fibers for use at high temperature in rigorousenvironment. The decent mechanical performance of BNfibers can be assured by well crystallinity and preferentialorientation of the BN crystallites in the direction parallelto the fiber axis [151]. Polybutylene terephthalate (PBT), awidely used plastic as an insulator in the electrical and elec-tronics industries, was reinforced in thermal conductivity byintroducing carbon fibers. However, this led to synchronousincreased electrical conductivity of PBT. The addition of BNfibers into the present composite was found to effectivelyreduce its electrical conductivity. Moreover, better tensileproperties and processability of the hybrid composite withcombined carbon and BN fibers was obtained [152].

One-dimensional materials offer interesting gas adsorp-tion properties, specially, hydrogen storage. CNTs wereconfirmed to possess the hydrogen uptake of up to 20 wt.%,although the reported value fluctuated markedly [153].Boron nitride nanomaterials with uniform electrical proper-ties were anticipated to exhibit good stability and high stor-age capacity. Ma et al. described for the first time the hydro-gen uptake of multiwalled BNNTs as 1.8–2.6 wt.% under∼10 MPa at room temperature [154]. Surface-modifiedBNNTs by SO2 with high surface area was measured tohave hydrogen storage of 1.2 wt.% at 77 K [69]. CollapsedBNNTs with increased specific surface area of 789.1 m2/gdisplayed enhanced hydrogen storage of up to 4.2 wt.%under ∼10 MPa at ambient temperature, the highest value

for BNNTs reported up to now [155]. This significantincrease was in fairly good agreement with the theoreticalpredication that high-surface-area BNNTs with ordered porestructure may be beneficial to the increase in hydrogenstorage [156]. Another concern stemmed from the used Ptnanoparticles existing in the final product. Both theoreticalcalculations and electrochemical hydrogen storage studyproposed that hybrid structure of BNNTs and hydrogen-adsorbing metallic nanoclusters may lead to improvedhydrogen storage performance [157–159]. Another solutioncan be the usage of carbon-doped BNNTs as theoreticallycalculated [160]. On the other hand, BN nanofibers can alsoadsorb hydrogen with storage capacity of 2.9 wt.% under∼10 MPa at room temperature as mentioned [135].

Recently, particularly in the last couples of years, BNNTswas emerging as innovative tool for nanomedicine [161],which was not discussed previously. Their counterpart,carbon nanotubes, has showed huge potential in this fieldand was investigated widely and intensively. However, littleexploitation was made to BNNTs due to their poor disper-sivity and unconfirmed biocompatibility. In 2002, Zhi et al.attempted primarily to check the compatibility of BNNTsand biomacromolecules by immobilizing ferritin proteinonto BNNTs [162]. After long-time stirring, they observedthe success immobilization, indicating a natural affinity of aprotein to BNNTs. If BNNTs were noncovalently function-alized by a complicated ester molecule, the immobilizationcan be done more efficiently with shortened stirring time.Very recently, several studies of their biocompatibility andinteraction with living cells were addressed. Chen et al.verified experimentally the noncytotoxicity of BNNTs withhigh purity and quality through culturing HEK 293 cells withBNNTs [163]. Fluorescence microscopy analysis revealedthat BNNTs coated by glycodendrimer with amphipathicdendritic structure can be directly bound to cell surfaceswithout causing any cellular toxicity (Figure 10). Their usageas cell delivery agents similar to carbon nanotubes wasalso confirmed. Another study further verified the benigncytocompatibility of BNNTs on human neuroblastoma cellsfor the first time [164]. BNNTs functionalized by Poly-L-lysine (PLL) can be used as nanotools to enable cellelectropermeabilization with low electric fields in an invitro test [165]. Ciofani et al. studied the feasibility ofusing PLL coated BNNTs as nanovectors in boron neutroncapture therapy (BNCT), a treatment method for severalviolent cancers, with folic acid as selective tumor targetingligand [100]. These experimental observations created newapplications of BNNTs in cell therapy, drug delivery, andother biomedical fields.

Other promising applications in field-emission devices,ultraviolet lasers, and insulating nanocables (e.g., AlN-BN,GaN-BN, SiC-BN) were also envisioned and investigated,which could be found elsewhere [29, 166].

6. Perspectives and Conclusions

Over the last two decades, synthesis, properties and appli-cations of 1D BN nanomaterials have been exploited anddeveloped as above reviewed.


0.2

0.3

0.4

0.5

0.1Th

erm

alco

ndu

ctiv

ity

(W/m

K)

1

0Blank

PMMA5 wt.%BNNT

10 wt.%BNNT

(a)

30

60

CTE of neat polymer

(×10−6K−1)

CTE of composite

(×10−6K−1)

TM

A(μ

m)

1

0

30 40 50

T/◦C

60 70

PVB 500 183

PS 96 48

PMMA 164 21

PEVA 180 16

PVB

PEVA

PVB/BNNT

PMMA

PS

PS/BNNTPMMA/BNNT

PEVA/BNNT

(b)

Figure 9: (a) A histogram for comparative study of thermal conductivity of BNNT-PMMA composites showing almost 3-fold enhancementwith BNNT loading fraction of 10 wt.% [143]. (b) Thermal mechanical analysis (TMA) and CTE improvement of four composites, PVB-BNNT, PS-BNNT, PMMA-BNNT and PEVA-BNNT [144]. It can be found that after introducing BNNTs into the pristine polymers, the CTEvalues were dramatically decreased. (a) Reprinted with permission of [143]. (b) Reprinted with permission of [144]. Copyright 2009 WileyInterScience.

[G-2] man

BNNT

(a) (b)

20 μm

(c)

20 μm

(d)

Figure 10: BNNTs for biotechnology [163]. (a) Illustration of glycodendrimer coated BNNTs in aqueous media. (b) [G-2] Man-BNNTs(left) were stable in aqueous solution for weeks and uncoated BNNTs (right) sedimentated. (c) [G-2] Man-BNNTs can be directly boundonto the CHO cell surface. (d) Depending on the carrier BNNT, BNNTs coated with FITC-labeled DNA were internalized by the CHO cells.Reprinted with permission of [163]. Copyright 2009 American Chemical Society.

As for BN nanotubes, large-scale production has beenachieved. However, much effort is still necessary to be madeto synthesis pure nanotubes with homogeneous structure.Alternatively, development of a more efficient purificationmethod is of great significance. Among the mass productionof various kinds of BNNTs, single-walled BNNTs is still oneof the research focus which are followed by comprehensiveproperty characterization. On the other hand, doped BNNTs

with modulated band structure, which may exhibit novelmagnetic and electrical properties, also have large space forfurther development.

BN nanowires can be studied intensively as buildingblocks in nanoscale devices. Synthesis of BN nanoribbonsstill requires unceasing exploitation from both theory andexperiment for the future application in nanoelectronics.As a promising candidate for super-lightweight engineering


fibers with high strength and excellent thermal and chemicalstability, boron nitride microscale and nanoscale fibers canprogress in solving basic theoretical issues and developingcost-effective methods for industrial production.

Overall, one-dimensional BN nanomaterials can be usedas promissing building blocks concerned about the electronicdevices, materials engineering, biomedical engineering andother emergent and important issues.

Acknowledgments

This work was supported by the National Nature Science ofChina (Grant nos. 20871075 and 20971079), the 973 Projectof China (no. 2005CB623601), the Independent InnovationFoundation of Shandong University (IIFSDU), and the Ph.D. Programs Foundation of Ministry of Education of China(no. 20070422046).

References

[1] S. Iijima, “Helical microtubules of graphitic carbon,” Nature,vol. 354, no. 6348, pp. 56–58, 1991.

[2] S. V. N. T. Kuchibhatla, A. S. Karakoti, D. Bera, and S.Seal, “One dimensional nanostructured materials,” Progressin Materials Science, vol. 52, no. 5, pp. 699–913, 2007.

[3] Y. Xia, P. Yang, Y. Sun et al., “One-dimensional nanos-tructures: synthesis, characterization, and applications,”Advanced Materials, vol. 15, no. 5, pp. 353–389, 2003.

[4] R. H. Baughman, A. A. Zakhidov, and W. A. de Heer,“Carbon nanotubes—the route toward applications,” Science,vol. 297, no. 5582, pp. 787–792, 2002.

[5] C. Zhi, Y. Bando, C. Tan, and D. Golberg, “Effective precursorfor high yield synthesis of pure BN nanotubes,” Solid StateCommunications, vol. 135, no. 1-2, pp. 67–70, 2005.

[6] Y. J. Chen, H. Z. Zhang, and Y. Chen, “Pure boron nitridenanowires produced from boron triiodide,” Nanotechnology,vol. 17, no. 3, pp. 786–789, 2006.

[7] Z.-G. Chen, J. Zou, G. Liu et al., “Novel boron nitride hollownanoribbons,” ACS Nano, vol. 2, no. 10, pp. 2183–2191, 2008.

[8] Y. Qiu, J. Yu, J. Yin et al., “Synthesis of continuous boronnitride nanofibers by solution coating electrospun templatefibers,” Nanotechnology, vol. 20, no. 34, Article ID 345603,2009.

[9] H. Zhang, J. Yu, Y. Chen, and J. F. Gerald, “Conicalboron nitride nanorods synthesized via the ball-milling andannealing method,” Journal of the American Ceramic Society,vol. 89, no. 2, pp. 675–679, 2006.

[10] X. Blase, A. Rubio, S. G. Louie, and M. L. Cohen, “Stabilityand band-gap constancy of boron nitride nanotubes,” Euro-physics Letters, vol. 28, no. 5, pp. 335–340, 1994.

[11] C. C. Tang, Y. Bando, T. Sato, and K. Kurashima, “Uni-form boron nitride coatings on silicon carbide nanowires,”Advanced Materials, vol. 14, no. 15, pp. 1046–1049, 2002.

[12] W. S. Jang, S. Y. Kim, J. Lee, J. Park, C. J. Park, and C. J.Lee, “Triangular GaN-BN core-shell nanocables: synthesisand field emission,” Chemical Physics Letters, vol. 422, no. 1–3, pp. 41–45, 2006.

[13] L.-W. Yin, Y. Bando, Y.-C. Zhu, D. Golberg, and M.-S. Li, “Atwo-stage route to coaxial cubic-aluminum-nitride-boron-nitride composite nanotubes,” Advanced Materials, vol. 16,no. 11, pp. 929–933, 2004.

[14] Y.-C. Zhu, Y. Bando, D.-F. Xue, F.-F. Xu, and D. Gol-berg, “Insulating tubular BN sheathing on semiconductingnanowires,” Journal of the American Chemical Society, vol.125, no. 47, pp. 14226–14227, 2003.

[15] Y. Zhang, K. Suenaga, C. Colliex, and S. Iijima, “Coaxialnanocable: silicon carbide and silicon oxide sheathed withboron nitride and carbon,” Science, vol. 281, no. 5379, pp.973–975, 1998.

[16] K. Suenaga, C. Colliex, N. Demoncy, A. Loiseau, H. Pascard,and F. Willaime, “Synthesis of nanoparticles and nanotubeswith well-separated layers of boron nitride and carbon,”Science, vol. 278, no. 5338, pp. 653–655, 1997.

[17] N. G. Chopra, R. J. Luyken, K. Cherrey et al., “Boron nitridenanotubes,” Science, vol. 269, no. 5226, pp. 966–967, 1995.

[18] A. Loiseau, F. Willaime, N. Demoncy, G. Hug, and H.Pascard, “Boron nitride nanotubes with reduced numbers oflayers synthesized by Arc discharge,” Physical Review Letters,vol. 76, no. 25, pp. 4737–4740, 1996.

[19] A. Loiseau, F. Willaime, N. Demoncy et al., “Boron nitridenanotubes,” Carbon, vol. 36, no. 5-6, pp. 743–752, 1998.

[20] Y. Saito, M. Maida, and T. Matsumoto, “Structures of boronnitride nanotubes with single-layer and multilayers producedby Arc discharge,” Japanese Journal of Applied Physics, vol. 38,no. 1, pp. 159–163, 1999.

[21] J. Cumings and A. Zettl, “Mass-production of boron nitridedouble-wall nanotubes and nanococoons,” Chemical PhysicsLetters, vol. 316, no. 3-4, pp. 211–216, 2000.

[22] M. V. P. Altoe, J. P. Sprunck, J.-C. P. Gabriel, and K. Bradley,“Nanococoon seeds for BN nanotube growth,” Journal ofMaterials Science, vol. 38, no. 24, pp. 4805–4810, 2003.

[23] D. P. Yu, X. S. Sun, C. S. Lee et al., “Synthesis of boronnitride nanotubes by means of excimer laser ablation at hightemperature,” Applied Physics Letters, vol. 72, no. 16, pp.1966–1968, 1998.

[24] G. W. Zhou, Z. Zhang, Z. G. Bai, and D. P. Yu, “Catalysteffects on formation of boron nitride nano-tubules synthe-sized by laser ablation,” Solid State Communications, vol. 109,no. 8, pp. 555–559, 1999.

[25] E. Bengu and L. D. Marks, “Single-walled BN nanostruc-tures,” Physical Review Letters, vol. 86, no. 11, pp. 2385–2387,2001.

[26] R. S. Lee, J. Gavillet, M. Lamy de la Chapelle et al., “Catalyst-free synthesis of boron nitride single-wall nanotubes with apreferred zig-zag configuration,” Physical Review B, vol. 64,no. 12, Article ID 121405, 4 pages, 2001.

[27] R. Arenal, O. Stephan, J.-L. Cochon, and A. Loiseau,“Root-growth mechanism for single-walled boron nitridenanotubes in laser vaporization technique,” Journal of theAmerican Chemical Society, vol. 129, no. 51, pp. 16183–16189, 2007.

[28] T. Laude, Y. Matsui, A. Marraud, and B. Jouffrey, “Long ropesof boron nitride nanotubes grown by a continuous laserheating,” Applied Physics Letters, vol. 76, no. 22, pp. 3239–3241, 2000.

[29] D. Golberg, Y. Bando, C. Tang, and C. Zni, “Boron nitridenanotubes,” Advanced Materials, vol. 19, no. 18, pp. 2413–2432, 2007.

[30] J. Wang, V. K. Kayastha, Y. K. Yap et al., “Low temperaturegrowth of boron nitride nanotubes on substrates,” NanoLetters, vol. 5, no. 12, pp. 2528–2532, 2005.

[31] Y. Chen, L. T. Chadderton, J. F. Gerald, and J. S. Williams,“A solid-state process for formation of boron nitride nan-otubes,” Applied Physics Letters, vol. 74, no. 20, pp. 2960–2962, 1999.


[32] Y. Chen, J. Fitz Gerald, J. S. Williams, and S. Bulcock,“Synthesis of boron nitride nanotubes at low temperaturesusing reactive ball milling,” Chemical Physics Letters, vol. 299,no. 3-4, pp. 260–264, 1999.

[33] Y. Chen, M. Conway, J. S. Williams, and J. Zou, “Large-quantity production of high-yield boron nitride nanotubes,”Journal of Materials Research, vol. 17, no. 8, pp. 1896–1899,2002.

[34] J. D. Fitz Gerald, Y. Chen, and M. J. Conway, “Nanotubegrowth during annealing of mechanically milled boron,”Applied Physics A, vol. 76, no. 1, pp. 107–110, 2003.

[35] J. Yu, Y. Chen, R. Wuhrer, Z. Liu, and S. P. Ringer, “Insitu formation of BN nanotubes during nitriding reactions,”Chemistry of Materials, vol. 17, no. 20, pp. 5172–5176, 2005.

[36] J. Yu, Y. Chen, R. G. Elliman, and M. Petravic, “Isotopicallyenriched 10BN nanotubes,” Advanced Materials, vol. 18, no.16, pp. 2157–2160, 2006.

[37] J. Yu, B. C. P. Li, J. Zou, and Y. Chen, “Influence of nitridinggases on the growth of boron nitride nanotubes,” Journal ofMaterials Science, vol. 42, no. 11, pp. 4025–4030, 2007.

[38] L. Li, C. P. Li, and Y. Chen, “Synthesis of boron nitridenanotubes, bamboos and nanowires,” Physica E, vol. 40, no.7, pp. 2513–2516, 2008.

[39] J. J. Velazquez-Salazar, E. Munoz-Sandoval, J. M. Romo-Herrera et al., “Synthesis and state of art characterizationof BN bamboo-like nanotubes: evidence of a root growthmechanism catalyzed by Fe,” Chemical Physics Letters, vol.416, no. 4–6, pp. 342–348, 2005.

[40] H. Choi, S. Y. Bae, W. S. Jang, J. Park, H. J. Song, and H.-J. Shin, “X-ray absorption near edge structure study of BNnanotubes and nanothorns,” Journal of Physical Chemistry B,vol. 109, no. 15, pp. 7007–7011, 2005.

[41] H. Chen, Y. Chen, Y. Liu, L. Fu, C. Huang, and D. Llewellyn,“Over 1.0 mm-long boron nitride nanotubes,” ChemicalPhysics Letters, vol. 463, no. 1–3, pp. 130–133, 2008.

[42] W. Han, Y. Bando, K. Kurashima, and T. Sato, “Synthesisof boron nitride nanotubes from carbon nanotubes by asubstitution reaction,” Applied Physics Letters, vol. 73, no. 21,pp. 3085–3087, 1998.

[43] D. Golberg, W. Han, Y. Bando, L. Bourgeois, K. Kurashima,and T. Sato, “Fine structure of boron nitride nanotubesproduced from carbon nanotubes by a substitution reaction,”Journal of Applied Physics, vol. 86, no. 4, pp. 2364–2366, 1999.

[44] W. Q. Han, L. Bourgeois, Y. Bando, K. Kurashima, andT. Sato, “Formation and structure of boron nitride conicalnanotubes,” Applied Physics A, vol. 71, no. 1, pp. 83–85, 2000.

[45] D. Golberg, Y. Bando, W. Han, K. Kurashima, and T. Sato,“Single-walled B-doped carbon, B/N-doped carbon and BNnanotubes synthesized from single-walled carbon nanotubesthrough a substitution reaction,” Chemical Physics Letters,vol. 308, no. 3-4, pp. 337–342, 1999.

[46] W.-Q. Han, W. Mickelson, J. Cumings, and A. Zettl, “Trans-formation of BxCyNz nanotubes to pure BN nanotubes,”Applied Physics Letters, vol. 81, no. 6, pp. 1110–1112, 2002.

[47] D. Golberg, Y. Bando, K. Kurashima, and T. Sato, “MoO3-promoted synthesis of multi-walled BN nanotubes from Cnanotube templates,” Chemical Physics Letters, vol. 323, no.1-2, pp. 185–191, 2000.

[48] E. Borowiak-Palen, T. Pichler, G. G. Fuentes et al., “Infraredresponse of multiwalled boron nitride nanotubes,” ChemicalCommunications, vol. 9, no. 1, pp. 82–83, 2003.

[49] Y. Bando, D. Golberg, M. Mitome, K. Kurashima, andT. Sato, “C to BN conversion in multi-walled nan-otubes as revealed by energy-filtering transmission electronmicroscopy,” Chemical Physics Letters, vol. 346, no. 1-2, pp.29–34, 2001.

[50] D. Golberg and Y. Bando, “Unique morphologies of boronnitride nanotubes,” Applied Physics Letters, vol. 79, no. 3, pp.415–417, 2001.

[51] D. Golberg, Y. Bando, K. Kurashima, and T. Sato, “Synthesisand characterization of ropes made of BN multiwallednanotubes,” Scripta Materialia, vol. 44, no. 8-9, pp. 1561–1565, 2001.

[52] D. Golberg, Y. Bando, K. Kurashima, and T. Sato, “Ropesof BN multi-walled nanotubes,” Solid State Communications,vol. 116, no. 1, pp. 1–6, 2000.

[53] F. L. Deepak, C. P. Vinod, K. Mukhopadhyay, A. Govindaraj,and C. N. R. Rao, “Boron nitride nanotubes and nanowires,”Chemical Physics Letters, vol. 353, no. 5-6, pp. 345–352, 2002.

[54] F. F. Xu and Y. Bando, “Structural characteristics of thetubular conical-helix of graphitic boron nitride,” Journal ofPhysical Chemistry B, vol. 108, no. 50, pp. 19233–19236, 2004.

[55] F. F. Xu, Y. Bando, R. Ma, D. Golberg, Y. Li, and M. Mitome,“Formation, structure, and structural properties of a newfilamentary tubular form: hollow conical-helix of graphiticboron nitride,” Journal of the American Chemical Society, vol.125, no. 26, pp. 8032–8038, 2003.

[56] X. Z. Wang, Q. Wu, Z. Hu, and Y. Chen, “Template-directedsynthesis of boron nitride nanotube arrays by microwaveplasma chemical reaction,” Electrochimica Acta, vol. 52, no.8, pp. 2841–2844, 2007.

[57] K. B. Shelimov and M. Moskovits, “Composite nanostruc-tures based on template-grown boron nitride nanotubules,”Chemistry of Materials, vol. 12, no. 1, pp. 250–254, 2000.

[58] M. Bechelany, S. Bernard, A. Brioude et al., “Synthesis ofboron nitride nanotubes by a template-assisted polymerthermolysis process,” Journal of Physical Chemistry C, vol.111, no. 36, pp. 13378–13384, 2007.

[59] Y. Wang, Y. Yamamoto, H. Kiyono, and S. Shimada, “Highlyordered boron nitride nanotube arrays with controllabletexture from ammonia borane by template-aided vapor-phase pyrolysis,” Journal of Nanomaterials, vol. 2008, ArticleID 606283, 7 pages, 2008.

[60] Y. Wang, S. Shimada, Y. Yamamoto, and N. Miyaura,“Preparation of h-BN nano-tubes, -bamboos, and -fibersfrom borazine oligomer with alumina porous template,”Materials Research Bulletin, vol. 43, no. 2, pp. 251–256, 2008.

[61] L. M. Cao, X. Y. Zhang, H. Tian, Z. Zhang, and W. K.Wang, “Boron nitride nanotube branched nanojunctions,”Nanotechnology, vol. 18, no. 15, Article ID 155605, 2007.

[62] N. Li, X. Li, W. Geng et al., “Template synthesis of boronnitride nanotubes in mesoporous silica SBA-15,” MaterialsLetters, vol. 59, no. 8-9, pp. 925–928, 2005.

[63] L. Guo and R. N. Singh, “Selective growth of boron nitridenanotubes by plasma-enhanced chemical vapor deposition atlow substrate temperature,” Nanotechnology, vol. 19, no. 6,Article ID 065601, 2008.

[64] C.-Y. Su, W.-Y. Chu, Z. Juang et al., “Large-scale synthesisof boron nitride nanotubes with iron-supported catalysts,”Journal of Physical Chemistry C, vol. 113, no. 33, pp. 14732–14738, 2009.

[65] C.-Y. Su, Z.-Y. Juang, K.-F. Chen et al., “Selective growth ofBoron nitride nanotubes by the plasma-assisted and iron-catalytic CVD methods,” Journal of Physical Chemistry C, vol.113, no. 33, pp. 14681–14688, 2009.


[66] O. R. Lourie, C. R. Jones, B. M. Bartlett, P. C. Gibbons, R.S. Ruoff, and W. E. Buhro, “CVD growth of boron nitridenanotubes,” Chemistry of Materials, vol. 12, no. 7, pp. 1808–1810, 2000.

[67] M. J. Kim, S. Chatterjee, S. M. Kim et al., “Double-walledboron nitride nanotubes grown by floating catalyst chemicalvapor deposition,” Nano Letters, vol. 8, no. 10, pp. 3298–3302,2008.

[68] C. Tang, Y. Bando, T. Sato, and K. Kurashima, “A novelprecursor for synthesis of pure boron nitride nanotubes,”Chemical Communications, no. 12, pp. 1290–1291, 2002.

[69] T. Terao, Y. Bando, M. Mitome et al., “Effective synthesisof surface-modified boron nitride nanotubes and relatednanostructures and their hydrogen uptake,” Physica E, vol.40, no. 7, pp. 2551–2555, 2008.

[70] C. C. Tang, X. X. Ding, X. T. Huang et al., “Effective growth ofboron nitride nanotubes,” Chemical Physics Letters, vol. 356,no. 3-4, pp. 254–258, 2002.

[71] C. C. Tang, Y. Bando, and D. Golberg, “Multi-walled BNnanotubes synthesized by carbon-free method,” Journal ofSolid State Chemistry, vol. 177, no. 8, pp. 2670–2674, 2004.

[72] D. Golberg, M. Mitome, Y. Bando, C. C. Tang, and C. Y. Zhi,“Multi-walled boron nitride nanotubes composed of diversecross-section and helix type shells,” Applied Physics A, vol. 88,no. 2, pp. 347–352, 2007.

[73] Z.-G. Chen, J. Zou, F. Li et al., “Growth of magnetic yard-glass shaped boron nitride nanotubes with periodic ironnanoparticles,” Advanced Functional Materials, vol. 17, no.16, pp. 3371–3376, 2007.

[74] R. Ma, Y. Bando, and T. Sato, “CVD synthesis of boron nitridenanotubes without metal catalysts,” Chemical Physics Letters,vol. 337, no. 1–3, pp. 61–64, 2001.

[75] R. Ma, Y. Bando, T. Sato, and K. Kurashima, “Growth,morphology, and structure of boron nitride nanotubes,”Chemistry of Materials, vol. 13, no. 9, pp. 2965–2971, 2001.

[76] R. Ma, Y. Bando, and T. Sato, “Controlled synthesis ofBN nanotubes, nanobamboos, and nanocables,” AdvancedMaterials, vol. 14, no. 5, pp. 366–368, 2002.

[77] R. Ma and Y. Bando, “Pyrolytic-grown B-C-N and BNnanotubes,” Science and Technology of Advanced Materials,vol. 4, no. 5, pp. 403–407, 2003.

[78] N. Fan, X. Ma, X. Liu, L. Xu, and Y. Qian, “The formation of alayer of Fe3O4 nanoplates between two carbon films,” Carbon,vol. 45, no. 9, pp. 1839–1846, 2007.

[79] Z. Ju, Z. Xing, C. Guo, L. Yang, L. Xu, and Y. Qian, “Sulfur-assisted approach for the low-temperature synthesis of β-SiC nanowires,” European Journal of Inorganic Chemistry, vol.2008, no. 24, pp. 3883–3888, 2008.

[80] L. Wang, L. Xu, C. Sun, and Y. Qian, “A general routefor the convenient synthesis of crystalline hexagonal boronnitride micromesh at mild temperature,” Journal of MaterialsChemistry, vol. 19, no. 14, pp. 1989–1994, 2009.

[81] L. Xu, J. Zhan, J. Hu et al., “High-yield synthesis of rhom-bohedral boron nitride triangular nanoplates,” AdvancedMaterials, vol. 19, no. 16, pp. 2141–2144, 2007.

[82] X. Wang, Y. Xie, and Q. Guo, “Synthesis of high qualityinorganic fullerene-like BN hollow spheres via a simplechemical route,” Chemical Communications, vol. 9, no. 21, pp.2688–2689, 2003.

[83] M. Li, L. Xu, C. Sun, Z. Ju, and Y. Qian, “Thermal-inducedshape evolution from uniform triangular to hexagonal r-BNnanoplates,” Journal of Materials Chemistry, vol. 19, no. 43,pp. 8086–8091, 2009.

[84] L. Xu, Y. Peng, Z. Meng et al., “A co-pyrolysis methodto boron nitride nanotubes at relative low temperature,”Chemistry of Materials, vol. 15, no. 13, pp. 2675–2680, 2003.

[85] J. Dai, L. Xu, Z. Fang et al., “A convenient catalytic approachto synthesize straight boron nitride nanotubes using synergicnitrogen source,” Chemical Physics Letters, vol. 440, no. 4–6,pp. 253–258, 2007.

[86] C. Sun, C. Guo, X. Ma, L. Xu, and Y. Qian, “A facile route toprepare boron nitride hollow particles at 450◦C,” Journal ofCrystal Growth, vol. 311, no. 14, pp. 3682–3686, 2009.

[87] Y. Shimizu, Y. Moriyoshi, H. Tanaka, and S. Komatsu, “Boronnitride nanotubes, webs, and coexisting amorphous phaseformed by the plasma jet method,” Applied Physics Letters,vol. 75, no. 7, pp. 929–931, 1999.

[88] C. Zhi, Y. Bando, C. C. Tang, Q. Huang, and D. Golberg,“Boron nitride nanotubes: functionalization and compos-ites,” Journal of Materials Chemistry, vol. 18, no. 33, pp. 3900–3908, 2008.

[89] C. Zhi, Y. Bando, C. Tang et al., “Covalent functionalization:towards soluble multiwalled boron nitride nanotubes,” Ange-wandte Chemie—International Edition, vol. 44, no. 48, pp.7932–7935, 2005.

[90] C. Zhi, Y. Bando, C. Tang, H. Kuwahara, and D. Golberg,“Grafting boron nitride nanotubes: from polymers to amor-phous and graphitic carbon,” Journal of Physical Chemistry C,vol. 111, no. 3, pp. 1230–1233, 2007.

[91] T. Ikuno, T. Sainsbury, D. Okawa, J. M. J. Frechet, and A.Zettl, “Amine-functionalized boron nitride nanotubes,” SolidState Communications, vol. 142, no. 11, pp. 643–646, 2007.

[92] S.-Y. Xie, W. Wang, K. A. S. Fernando, X. Wang, Y. Lin,and Y.-P. Sun, “Solubilization of boron nitride nanotubes,”Chemical Communications, no. 29, pp. 3670–3672, 2005.

[93] T. Sainsbury, T. Ikuno, D. Okawa, D. Pacile, J. M. J. Frechet,and A. Zettl, “Self-assembly of gold nanoparticles at thesurface of amine- and thiol-functionalized boron nitridenanotubes,” Journal of Physical Chemistry C, vol. 111, no. 35,pp. 12992–12999, 2007.

[94] Q. Huang, Y. Bando, C. Zhi et al., “Chemical peeling andbranching of boron nitride nanotubes in dimethyl sulfoxide,”Angewandte Chemie—International Edition, vol. 45, no. 13,pp. 2044–2047, 2006.

[95] C. Y. Zhi, Y. Bando, T. Terao, C. C. Tang, H. Kuwahara, andD. Golberg, “Chemically activated boron nitride nanotubes,”Chemistry - An Asian Journal, vol. 4, no. 10, pp. 1536–1540,2009.

[96] W. Wang, Y. Bando, C. Zhi, W. Fu, E. Wang, and D. Gol-berg, “Aqueous noncovalent functionalization and controllednear-surface carbon doping of multiwalled boron nitridenanotubes,” Journal of the American Chemical Society, vol.130, no. 26, pp. 8144–8145, 2008.

[97] C. Zhi, Y. Bando, C. Tang, R. Xie, T. Sekiguchi, and D.Golberg, “Perfectly dissolved boron nitride nanotubes due topolymer wrapping,” Journal of the American Chemical Society,vol. 127, no. 46, pp. 15996–15997, 2005.

[98] C. Zhi, Y. Bando, C. Tang et al., “Purification of boron nitridenanotubes through polymer wrapping,” Journal of PhysicalChemistry B, vol. 110, no. 4, pp. 1525–1528, 2006.

[99] C. Zhi, Y. Bando, W. Wang, C. Tang, H. Kuwahara, andD. Golberg, “DNA-mediated assembly of boron nitridenanotubes,” Chemistry - An Asian Journal, vol. 2, no. 12, pp.1581–1585, 2007.


[100] G. Ciofani, V. Raffa, A. Menciassi, and A. Cuschieri, “Folatefunctionalized boron nitride nanotubes and their selectiveuptake by glioblastoma multiforme cells: implications fortheir use as boron carriers in clinical boron neutron capturetherapy,” Nanoscale Research Letters, vol. 4, no. 2, pp. 113–121, 2009.

[101] J. Yu, Y. Chen, and B. M. Cheng, “Dispersion of boronnitride nanotubes in aqueous solution with the help of ionicsurfactants,” Solid State Communications, vol. 149, no. 19-20,pp. 763–766, 2009.

[102] S. Pal, S. R. C. Vivekchand, A. Govindaraj, and C. N. R. Rao,“Functionalization and solubilization of BN nanotubes byinteraction with Lewis bases,” Journal of Materials Chemistry,vol. 17, no. 5, pp. 450–452, 2007.

[103] A. Maguer, E. Leroy, L. Bresson, E. Doris, A. Loiseau, and C.Mioskowski, “A versatile strategy for the functionalization ofboron nitride nanotubes,” Journal of Materials Chemistry, vol.19, no. 9, pp. 1271–1275, 2009.

[104] Y. Li, Z. Zhou, and J. Zhao, “Functionalization of BNnanotubes with dichlorocarbenes,” Nanotechnology, vol. 19,no. 1, Article ID 015202, 2008.

[105] F. L. Cao, W. Ren, X. Y. Xu, et al., “Boron nitride nanotubesfunctionalized by a series of carbenes,” Physical ChemistryChemical Physics, vol. 11, no. 29, pp. 6256–6262, 2009.

[106] R. Sen, B. C. Satishkumar, A. Govindaraj et al., “B-C-N, C-Nand B-N nanotubes produced by the pyrolysis of precursormolecules over Co catalysts,” Chemical Physics Letters, vol.287, no. 5-6, pp. 671–676, 1998.

[107] Y. Zhang, H. Gu, K. Suenaga, and S. Iijima, “Heterogeneousgrowth of B-C-N nanotubes by laser ablation,” ChemicalPhysics Letters, vol. 279, no. 5-6, pp. 264–269, 1997.

[108] D. Golberg, P. S. Dorozhkin, Y. Bando et al., “Cables of BN-insulated B-C-N nanotubes,” Applied Physics Letters, vol. 82,no. 8, pp. 1275–1277, 2003.

[109] D. Golberg, P. Dorozhkin, Y. Bando, M. Hasegawa, and Z.-C.Dong, “Semiconducting B-C-N nanotubes with few layers,”Chemical Physics Letters, vol. 359, no. 3-4, pp. 220–228, 2002.

[110] D. Golberg, Y. Bando, K. Kurashima, and T. Sato, “Synthesis,HRTEM and electron diffraction studies of B/N-doped, Cand BN nanotubes,” Diamond and Related Materials, vol. 10,no. 1, pp. 63–67, 2001.

[111] C. Tang, Y. Bando, Y. Huang et al., “Fluorination andelectrical conductivity of BN nanotubes,” Journal of theAmerican Chemical Society, vol. 127, no. 18, pp. 6552–6553,2005.

[112] F. Li, Z. Zhu, X. Yao et al., “Fluorination-induced magnetismin boron nitride nanotubes from ab initio calculations,”Applied Physics Letters, vol. 92, no. 10, Article ID 102515,2008.

[113] L. Lai, W. Song, J. Lu et al., “Structural and electronicproperties of fluorinated boron nitride nanotubes,” Journalof Physical Chemistry B, vol. 110, no. 29, pp. 14092–14097,2006.

[114] H. Liu, G. Zhou, Q. Yan et al., “Structural and electronicproperties of fluorinated double-walled boron nitride nan-otubes: effect of interwall interaction,” Physical Review B, vol.75, no. 12, Article ID 125410, 6 pages, 2007.

[115] S. Xu, Y. Fan, J. Luo et al., “Phonon characteristics andphotoluminescence of bamboo structured silicon-dopedboron nitride multiwall nanotubes,” Applied Physics Letters,vol. 90, no. 1, Article ID 013115, 2007.

[116] Y. J. Cho, C. H. Kim, H. S. Kim et al., “Electronic struc-ture of Si-doped BN nanotubes using X-ray photoelectronspectroscopy and first-principles calculation,” Chemistry ofMaterials, vol. 21, no. 1, pp. 136–143, 2009.

[117] H. Chen, Y. Chen, C. P. Li et al., “Eu-doped boronnitride nanotubes as a nanometer-sized visible-light source,”Advanced Materials, vol. 19, no. 14, pp. 1845–1848, 2007.

[118] Z.-G. Chen, J. Zou, Q. Liu et al., “Self-assembly andcathodoluminescence of microbelts from Cu-doped boronnitride nanotubes,” ACS Nano, vol. 2, no. 8, pp. 1523–1532,2008.

[119] J. Wu and W. Zhang, “Tuning the magnetic and transportproperties of boron-nitride nanotubes via oxygen-doping,”Solid State Communications, vol. 149, no. 11-12, pp. 486–490,2009.

[120] G. Rahman and S. C. Hong, “Possible magnetism of Be-doped boron nitride nanotubes,” Journal of Nanoscience andNanotechnology, vol. 8, no. 9, pp. 4711–4713, 2008.

[121] X. Wu, J. L. Yang, and X. C. Zeng, “Adsorption of hydrogenmolecules on the platinum-doped boron nitride nanotubes,”Journal of Chemical Physics, vol. 125, no. 4, Article ID 044704,2006.

[122] H. Kokten, H. Ustunel, and S. Erkoc, “Structural, electronicand magnetic properties of BN nanotubes doped with Mnand Cr: exploring the potential for device technology,”Journal of Computational and Theoretical Nanoscience, vol. 6,no. 4, pp. 926–932, 2009.

[123] K. F. Huo, Z. Hu, F. Chen et al., “Synthesis of boron nitridenanowires,” Applied Physics Letters, vol. 80, no. 19, pp. 3611–3613, 2002.

[124] K. F. Huo, Z. Hu, J. J. Fu et al., “Microstructure and growthmodel of periodic spindle-unit BN nanotubes by nitridingFe-B nanoparticles with nitrogen/ammonia mixture,” Journalof Physical Chemistry B, vol. 107, no. 41, pp. 11316–11320,2003.

[125] D.-M. Tang, C. Liu, and H.-M. Cheng, “Controlled synthesisof quasi-one-dimensional boron nitride nanostructures,”Journal of Materials Research, vol. 22, no. 10, pp. 2809–2816,2007.

[126] Y. J. Chen, B. Chi, D. C. Mahon, and Y. Chen, “An effectiveapproach to grow boron nitride nanowires directly onstainless-steel substrates,” Nanotechnology, vol. 17, no. 12, pp.2942–2946, 2006.

[127] C.-H. Park and S. G. Louie, “Energy gaps and stark effect inboron nitride nanoribbons,” Nano Letters, vol. 8, no. 8, pp.2200–2203, 2008.

[128] V. Barone and J. E. Peralta, “Magnetic boron nitride nanorib-bons with tunable electronic properties,” Nano Letters, vol. 8,no. 8, pp. 2210–2214, 2008.

[129] H. Z. Zhang, Q. Zhao, J. Yu, D. P. Yu, and Y. Chen, “Field-emission characteristics of conical boron nitride nanorods,”Journal of Physics D, vol. 40, no. 1, pp. 144–147, 2007.

[130] L.-X. Lin, Y. Zheng, Z.-H. Li, X.-N. shen, and K.-M. Wei,“A simple method to synthesize polyhedral hexagonal boronnitride nanofibers,” Solid State Sciences, vol. 9, no. 12, pp.1099–1104, 2007.

[131] B. Toury, P. Miele, D. Cornu, H. Vincent, and J. Bouix,“Boron nitride fibers prepared from symmetric and asym-metric alkylaminoborazines,” Advanced Functional Materials,vol. 12, no. 3, pp. 228–234, 2002.

[132] D. Cornu, P. Miele, R. Faure, B. Bonnetot, H. Mongeot,and J. Bouix, “Conversion of B(NHCH3)3 into boron nitrideand polyborazine fibres and tubular BN structures derived


therefrom,” Journal of Materials Chemistry, vol. 9, no. 3, pp.757–761, 1999.

[133] T. Wideman and L. G. Sneddon, “Dipentylamine-modifimelt-spinnableed polyborazylene: a new, melt-spinnable polymeric precursor to boron nitride ceramicfibers,” Chemistry of Materials, vol. 8, no. 1, pp. 3–5, 1996.

[134] B. Toury, S. Bernard, D. Cornu, F. Chassagneux, J.-M.Letoffe, and P. Miele, “High-performance boron nitridefibers obtained from asymmetric alkylaminoborazine,” Jour-nal of Materials Chemistry, vol. 13, no. 2, pp. 274–279, 2003.

[135] R. Ma, Y. Bando, T. Sato et al., “Synthesis of boron nitridenanofibers and measurement of their hydrogen uptakecapacity,” Applied Physics Letters, vol. 81, no. 27, pp. 5225–5227, 2002.

[136] Y. Qiu, J. Yu, J. Rafique, J. Yin, X. Bai, and E. Wang, “Large-scale production of aligned long boron nitride nanofibers bymultijet/multicollector electrospinning,” Journal of PhysicalChemistry C, vol. 113, no. 26, pp. 11228–11234, 2009.

[137] C. Zhi, Y. Bando, C. Tang, and D. Golberg, “Engineering ofelectronic structure of boron-nitride nanotubes by covalentfunctionalization,” Physical Review B, vol. 74, no. 15, ArticleID 153413, 2006.

[138] W.-Q. Han, H.-G. Yu, C. Zhi et al., “Isotope effect on bandgap and radiative transitions properties of boron nitridenanotubes,” Nano Letters, vol. 8, no. 2, pp. 491–494, 2008.

[139] J. Yu, D. Yu, Y. Chen et al., “Narrowed bandgaps and strongerexcitonic effects from small boron nitride nanotubes,” Chem-ical Physics Letters, vol. 476, no. 4–6, pp. 240–243, 2009.

[140] Y. Chen, J. Zou, S. J. Campbell, and G. L. Caer, “Boron nitridenanotubes: pronounced resistance to oxidation,” AppliedPhysics Letters, vol. 84, no. 13, pp. 2430–2432, 2004.

[141] C. W. Chang, W.-Q. Han, and A. Zettl, “Thermal conductiv-ity of B-C-N and BN nanotubes,” Applied Physics Letters, vol.86, no. 17, Article ID 173102, 3 pages, 2005.

[142] N. G. Chopra and A. Zettl, “Measurement of the elasticmodulus of a multi-wall boron nitride nanotube,” Solid StateCommunications, vol. 105, no. 5, pp. 297–300, 1998.

[143] C. Zhi, Y. Bando, W. L. Wang, C. C. Tang, H. Kuwahara,and D. Golberg, “Mechanical and thermal properties ofpolymethyl methacrylate-BN nanotube composites,” Journalof Nanomaterials, vol. 2008, no. 1, Article ID 642036, 2008.

[144] C. Zhi, Y. Bando, T. Terao, C. Tang, H. Kuwahara, and D.Golberg, “Towards thermoconductive, electrically insulatingpolymeric composites with boron nitride nanotubes asfillers,” Advanced Functional Materials, vol. 19, no. 12, pp.1857–1862, 2009.

[145] Q. Huang, Y. Bando, X. Xu et al., “Enhancing superplasticityof engineering ceramics by introducing BN nanotubes,”Nanotechnology, vol. 18, no. 48, Article ID 485706, 2007.

[146] C. Zhi, Y. Bando, C. Tang, S. Honda, H. Kuwahara, and D.Golberg, “Boron nitride nanotubes/polystyrene composites,”Journal of Materials Research, vol. 21, no. 11, pp. 2794–2800,2006.

[147] H. Y. Ng, X. Lu, and S. K. Lau, “Thermal conductivityof boron nitride-filled thermoplastics: effect of filler char-acteristics and composite processing conditions,” PolymerComposites, vol. 26, no. 6, pp. 778–790, 2005.

[148] W. Zhou, S. Qi, Q. An, H. Zhao, and N. Liu, “Thermalconductivity of boron nitride reinforced polyethylene com-posites,” Materials Research Bulletin, vol. 42, no. 10, pp. 1863–1873, 2007.

[149] K. C. Yung and H. Liem, “Enhanced thermal conductivity ofboron nitride epoxy-matrix composite through multi-modalparticle size mixing,” Journal of Applied Polymer Science, vol.106, no. 6, pp. 3587–3591, 2007.

[150] K. Sato, H. Horibe, T. Shirai et al., “Thermally conductivecomposite films of hexagonal boron nitride and poly-imide with affinity-enhanced interfaces,” Journal of MaterialsChemistry, vol. 20, no. 14, pp. 2749–2752, 2010.

[151] B. Toury, D. Cornu, F. Chassagneux, and P. Miele, “Completecharacterisation of BN fibres obtained from a new polybo-rylborazine,” Journal of the European Ceramic Society, vol. 25,no. 2-3, pp. 137–141, 2005.

[152] H. Y. Ng, X. Lu, and S. K. Lau, “Thermal conductivity,electrical resistivity, mechanical, and rheological propertiesof thermoplastic composites filled with boron nitride andcarbon fiber,” Polymer Composites, vol. 26, no. 1, pp. 66–73,2005.

[153] P. Chen, X. Wu, J. Lin, and K. L. Tan, “High H2 uptake byalkali-doped carbon nanotubes under ambient pressure andmoderate temperatures,” Science, vol. 285, no. 5424, pp. 91–93, 1999.

[154] R. Ma, Y. Bando, H. Zhu, T. Sato, C. Xu, and D. Wu,“Hydrogen uptake in boron nitride nanotubes at roomtemperature,” Journal of the American Chemical Society, vol.124, no. 26, pp. 7672–7673, 2002.

[155] C. Tang, Y. Bando, X. Ding, S. Qi, and D. Golberg, “Catalyzedcollapse and enhanced hydrogen storage of BN nanotubes,”Journal of the American Chemical Society, vol. 124, no. 49, pp.14550–14551, 2002.

[156] S.-H. Jhi, “Activated boron nitride nanotubes: a potentialmaterial for room-temperature hydrogen storage,” PhysicalReview B, vol. 74, no. 15, Article ID 155424, 4 pages, 2006.

[157] Z. Zhou, J. Zhao, Z. Chen et al., “Comparative study ofhydrogen adsorption on carbon and BN nanotubes,” Journalof Physical Chemistry B, vol. 110, no. 27, pp. 13363–13369,2006.

[158] X. Chen, X. P. Gao, H. Zhang et al., “Preparation and elec-trochemical hydrogen storage of boron nitride nanotubes,”Journal of Physical Chemistry B, vol. 109, no. 23, pp. 11525–11529, 2005.

[159] X. M. Li, W. Q. Tian, X.-R. Huang, C.-C. Sun, and L. Jiang,“Adsorption of hydrogen on novel Pt-doped BN nanotube:a density functional theory study,” Journal of MolecularStructure, vol. 901, no. 1–3, pp. 103–109, 2009.

[160] R. J. Baierle, P. Piquini, T. M. Schmidt, and A. Fazzio,“Hydrogen adsorption on carbon-doped boron nitride nan-otube,” Journal of Physical Chemistry B, vol. 110, no. 42, pp.21184–21188, 2006.

[161] G. Ciofani, V. Raffa, A. Menciassi, and A. Cuschieri, “Boronnitride nanotubes: an innovative tool for nanomedicine,”Nano Today, vol. 4, no. 1, pp. 8–10, 2009.

[162] C. Zhi, Y. Bando, C. Tang, and D. Golberg, “Immobilizationof proteins on boron nitride nanotubes,” Journal of theAmerican Chemical Society, vol. 127, no. 49, pp. 17144–17145, 2005.

[163] X. Chen, P. Wu, M. Rousseas et al., “Boron nitride nanotubesare noncytotoxic and can be functionalized for interactionwith proteins and cells,” Journal of the American ChemicalSociety, vol. 131, no. 3, pp. 890–891, 2009.

[164] G. Ciofani, V. Raffa, A. Menciassi, and A. Cuschieri,“Cytocompatibility, interactions, and uptake of polyethyl-eneimine-coated boron nitride nanotubes by living cells:confirmation of their potential for biomedical applications,”


Biotechnology and Bioengineering, vol. 101, no. 4, pp. 850–858, 2008.

[165] V. Raffa, G. Ciofani, and A. Cuschieri, “Enhanced low voltagecell electropermeabilization by boron nitride nanotubes,”Nanotechnology, vol. 20, no. 7, Article ID 075104, 2009.

[166] R. Ma, D. Golberg, Y. Bando, and T. Sasaki, “Syntheses andproperties of B-C-N and BN nanostructures,” PhilosophicalTransactions of the Royal Society A, vol. 362, no. 1823, pp.2161–2186, 2004.

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