Carbon Boron Nitride Nanotubes Research Articles

Significance analysis of the attenuation coefficient of vibrations in a boron nitride–carbon nanotube under buckling and fracture: A molecular dynamics study

Boron nitride–carbon nanotubes (BN–CNTs), serving as nanomass sensors, exhibit fatigue characteristics, such as buckling or bond breakage, under impact from measured particles. However, the impact of such damage on the functionality of BN–CNTs remains unclear. Here, we use molecular dynamics simulations to investigate the performance of BN–CNTs mass sensors under impact by C60 particles, focusing on three critical states: buckling, bond breakage, and coexisting buckling and bond breakage. An analysis of the impact stress and mass responsivity shows that damaged beams have a lower mass detection capability than undamaged beams. The results of a paired t-test and an analysis of the decay coefficients and vibration frequencies of damaged nanobeams show that damaged nanobeams have a significantly lower quality factor than undamaged nanobeams. We use an energy equation to analyze the impact process of nanobeams for the first time, revealing that the change in the potential energy of the beam is a crucial influence factor of the beam critical state. This study provides insights into the damage to nanoscale mass sensors caused by impact.

Enhanced dielectric performance and thermal conductivity of the polyetherketoneketone composite films prepared via a facile template spray coating method

Polyetherketoneketone (PEKK) is a specialized engineering plastic renowned for its exceptional strength, high temperature resistance and chemical resistance. However, the high melting point of PEKK restricts its processing methods to traditional techniques such as melt extrusion, hot pressing, and molding, significantly limiting its application in the field of microelectronic devices. In this study, a facile template spray coating method was proposed to prepare highly flexible PEKK films. Furthermore, functionalized boron nitride-carbon nanotube (BN-CNT) hybrid fillers were prepared and incorporated into the PEKK matrix. The results demonstrated that when the content of BN-CNT hybrid filler was 5 wt%, the dielectric constant of the composite film ranges from 2.2 to 1.8 in the frequency range of 100–200000 Hz, with a dielectric loss value below 0.03. When the content of the hybrid filler increased to 20 wt%, the enhanced thermal conductive network results in a 640% increase in thermal conductivity compared to pure PEKK. The enhanced thermal conductivity of the composite films promoted heat dissipation of the computer CPU and accelerated the cooling rate. These findings demonstrate the great potential of the PEKK composite films for diverse applications in microelectronic devices.

Flexible Thermoelectric Films Based on Bi2Te3 Nanowires and Boron Nitride Nanotube Networks with Carbon Doping.

Energy recovery and reuse, industrial waste heat, and thermal energy recovery and conversion in emerging electronic devices are topics of widespread interest. Flexible composite thermoelectric (TE) films have become the key to TE conversion, and many studies and synthesis methods related to them have made great progress. However, little research has been performed on the corresponding composites of typical TE materials with low-dimensional nanotubular materials, particularly modulation of the overall TE properties using doped low-dimensional nanotubular materials. In this work, high-quality bismuth telluride (Bi2Te3) nanowires and boron nitride nanotubes (BNNTs) were prepared using electrolytic deposition and high-temperature catalytic deposition, respectively. Bi2Te3-BNNTs composite films were prepared using a solvent hot pressing method. The Bi2Te3-BNNTs composite film conductivity reached 179.6 S/cm at room temperature (300 K), the corresponding Seebeck coefficient was 171.4 μV/K, and the power factor (PF) was 52.8 nW/mK2. Carbon doping of BNNTs resulted in carbon-boron nitride nanotubes (BCNNTs), and Bi2Te3-BNNTs composite films were prepared. The Bi2Te3-BCNNTs composite films obtained a conductivity of 4629.6 S/cm, at room temperature (300 K), a corresponding Seebeck coefficient of 181.2 μV/K, and a PF of 1520.0 nW/mK2. This study has important reference value for the application of TE conversion. Moreover, the electrical conductivity decreased by no more than 10% after 400 cycles of bending tests, and the electrical conductivity showed signs of recovery after repressing thermally, which undoubtedly proves that Bi2Te3-BCNNTs composite films have good flexibility and thermal stability, and this has contributed to the application and promotion of flexible thermoelectric materials.

Adsorbing CNCl on pristine, C-, and Al-doped boron nitride nanotubes: A density functional theory study

The density functional theory (DFT) framework was used to investigate the intermolecular interactions between cyanogen chloride (CNCl) pollutant gas molecule with pristine boron nitride nanotubes (BNNT), Al-doped boron nitride nanotubes (BNAlNT), and carbon boron nitride nanotubes (BC2NNT). The geometric structures of the resulting systems have been optimized using different methods, including B3LYP-D3(GD3BJ)/6-311G(d), ωB97XD/6-311G(d), and M06-2X/6-311G(d). The computed adsorption energies suggest that the studied nanotubes can enhance adsorption of CNCl, and thus promote its detection when employed as sensing materials. Wave function analysis has been implemented to study the type of intermolecular interactions at ωB97XD/6-311G(d,p) level of theory. Natural bond orbital (NBO) analysis has been used to study the charge transfer and bond order. Quantum theory of atoms in molecules (QTAIM) analysis has also been used to determine the type of interactions between the target gas and the nanotubes. To investigate the weak intermolecular interactions we also carried out non-covalent interaction analysis (NCI). The results also indicate that the CNCl-nanotube systems are created through physisorption as they are dominated by non-covalent interactions. The predicted adsorption energies increase as follows: BNAlNT: −1.175 eV > BC2NNT: −0.281 eV > BNNT: −0.256 eV; this shows that the aluminum-doped boron nitride nanotube is the best option from promoting adsorption of the target gas among them. The HOMO–LUMO energy gaps were as follows: BNNT: 7.090, BNAlNT: 9.193, and BC2NNT: 7.027 eV at B3LYP-D3/6-311G(d) level of theory.

Thermal conductivities of hydrogen encapsulated boron nitride and hybrid boron nitride – carbon nanotubes using molecular dynamics simulations

In this work, we investigated the thermal conductivities of boron nitride nanotubes (BNNTs) and carbon nanotubes (CNTs) as potential hydrogen storage materials using atomistic nonequilibrium molecular dynamics (NEMD) simulations. Pristine and defective (containing B/N/C single atom vacancy or B-N double atom vacancies) capped armchair BNNTs and BN-C heteronanotubes have been studied. Furthermore, thermal conduction in BNNT, CNT, and BN(50%)-C(50%) heteronanotubes with varying amounts of encapsulated H2 molecules has been evaluated. We compare the performance of the reactive forcefield ReaxFF with non-reactive Tersoff-adaptive intermolecular reactive empirical bond order (AIREBO)-Lennard-Jones (TALJ) potentials combination. The ReaxFF potential yielded consistently lower thermal conductivity (k) for all the nanotubes. However, it provides a better qualitative prediction of thermal transport in the nanotubes (in terms of k reduction due to defects and entrapped H2, and sensitivity to composition as reflected in the phonon density of states) whereas Tersoff/TALJ potentials provide a better quantitative prediction of k while failing to account for acoustic phonon details. Near-linear mixing rule for k across the CNT-BNNT composition suggested by both potentials indicates smooth interfacial heat transport at the heterojunctions.

The Effect of an External Electric Field on the Electronic Properties of Defective CBN Nanotubes: A Density Functional Theory Approach

We investigated the effects of applying an external electric field on the electronic properties of Stone-Wales (SW) defective carbon-boron-nitride nanotubes (CBN) using first principles calculations. The defective CBN nanotubes were modeled by introducing Stone–Wales defects in the boron-nitride segment (BN-SW), the carbon segment (C-SW), and the carbon-boron-nitride interface segment (CBN-SW). Initially, we studied the formation energies and the structural stability for all models. As a result of adding the SW defects, the calculated bandgap values of the C-SW and CBN-SW models showed significant changes compared to the pristine CBN nanotube. Meanwhile, the BN-SW model showed a slight bandgap change because of the strong covalent bonding between the boron and nitrogen atoms. Applying a transverse electric field induced a fast bandgap closing response in all models, indicating a rapid semiconductor-to-metal phase transition. The defective C-SW and CBN-SW models demonstrated unique bandgap closing patterns in response to applied transverse and longitudinal electric fields, while pristine and BN-SW models had similar bandgap responses.

On the nonlinear vibration and static deflection problems of actuated hybrid nanotubes based on the stress-driven nonlocal integral elasticity

In the present paper, the effects of material properties, nonlocal parameter, Lorentz and electric forces on maximum static deflections and natural frequencies of actuated hybrid carbon/boron-nitride nanotubes (CBNNT) subjected to thermal loads are studied for the first time. The displacement field of the nanotube satisfies assumptions of the Bernoulli–Euler beam theory. The Green-Lagrange small strains and moderate rotations for geometric nonlinearity of the nanotube are taken into consideration. Two nonlinear governing equations of motion for carbon and boron-nitride parts of the clamped nanotube are derived using the d'Alembert principle and the stress-driven nonlocal integral elasticity theory. Solution to the formulated nonlinear boundary value problem was obtained using the Galerkin modal expansion method. Validation of obtained results and parametric study are comprehensively presented. Obtained results show effect of variation of temperature, nonlocal parameter, ratio of length of carbon and boron-nitride components, direct current (DC) and alternating current (AC) voltages on shifting of the fundamental frequency and maximum deflection of hybrid nanotube.

Nonlinear dynamic behavior of a clamped–clamped beam from BNC nanotube impacted by fullerene

The nonlinear dynamic behavior of a clamped–clamped nanobeam built with boron nitride carbon (BNC) nanotube is investigated as for its potential application in a mass sensor. To make it anisotropic in terms of bending stiffness, the cross section of the tube contains symmetrically two B–N zones and two carbon zones which accommodate 60% of atoms in the whole nanotube. The dynamic behavior of the nanosensor, colliding with a high-speed $$\hbox {C}_{60}$$ at the central part of the beam, is evaluated using molecular dynamics simulations and fast Fourier transform approaches. Results obtained show that the amplitude of vibration of the tube depends on the magnitude $$(v_{\mathrm{In}})$$ and direction ( $$\theta $$ ) of the incident velocity of the $$\hbox {C}_{60}$$ . When $$v_{\mathrm{In}}$$ is higher than a critical value, the beam will be damaged in the collision. The position of the damage on the nanobeam and the critical value depend on $$\theta $$ . If $$v_{\mathrm{In}}$$ is lower than the critical value, the first-order frequency of the vibration at the beam centroid is lower when impacted by a faster $$\hbox {C}_{60}$$ . The second-order frequency depends on the configuration of the beam’s central cross section. The intervals of the first-order frequency with respect to $$\theta = 0^{\circ }$$ and $$90^{\circ }$$ are not overlapped. These findings hint that a BNC nanobeam can be used to measure the mass of a molecular under a known incident velocity or an incident velocity of a known molecular via this model.

Reversing rotation of a nanomotor by introducing a braking BNC nanotube

To adjust the rotation of a CNT-based nanomotor, a boron-nitride carbon nanotube is adopted as a braking tube. The dynamic response of the rotor in the motor is tested using molecular dynamics simulations. It is discovered that not only the rotational speed of the rotor can be reduce by improving insert depth of the braking tube into the rotor, but also the rotational direction of the rotor can be reversed. Once the reverse rotation is obtained, it is independent on the insert depth, but very sensitive to the environmental temperature. The properties will benefit design of a rotary nanodevice with controllable rotation as output signal.

Superior interfacial mechanical properties of boron nitride-carbon nanotube reinforced nanocomposites: A molecular dynamics study

The newly discovered hybrid boron nitride-carbon nanotubes (BN-CNTs) are very promising for the innovative design of next-generation nanocomposites. In this work, molecular dynamics simulation-based pull-out studies have been performed to characterise the interfacial properties of BN-CNT reinforced polyethylene (PE) composites. Our results show that the interfacial shear strength (ISS) of BN-CNT/PE nanocomposites strongly depends on the BN composition and the connecting pattern of the C/BN fragment in the embedded BN-CNTs. Specifically, an ISS about 90% greater than that of the PE composite reinforced by the conventional carbon nanotube (CNT) is detected in the composite reinforced by the BN-CNT with certain connecting pattern and BN concentration. Such a superior ISS in the BN-CNT/PE composites is found to mainly originate from the unique rough van der Waals surface of the BN-CNT and the greater binding interaction between the embedded BN-CNT and the PE matrix, both of which contribute to enhancing the interface load transfer of nanocomposites. The enhanced ISS detected in the composite reinforced by BN-CNTs suggests that, compared with the most commonly used CNT, the novel BN-CNT can be a better reinforcement candidate in the design of nanocomposites.

Beat vibration of hybrid boron nitride-carbon nanotubes – A new avenue to atomic-scale mass sensing

In this paper a beat phenomenon is reported in molecular dynamics simulations for vibrating boron nitride-carbon nanotubes (BN-CNTs) and then analysed based on a continuum mechanics theory. It was shown that the distinctive dynamic behaviour is a result of the superposition of two orthogonal transverse vibrations whose frequencies are slightly different due to the oval cross-section of the hybrid nanotubes. In particular, the interaction between the two vibrations in BN-CNTs will facilitate to resolve the fundamental issue in developing mass nanosensors for atomic-scale mass measuring. To reach this goal, efforts should be made to maintain high quality factor of the BN-CNT oscillating system by minimising the damping effect of its surrounding environment. This issue turns out to be essential for the beat mode-based nanosensors as large damping will reduce the hybrid nanotubes to conventional resonators with only one transverse vibration same as that reported for homogeneous nanotubes.

Mechanical properties of hybrid boron nitride–carbon nanotubes

Hybrid boron nitride–carbon nanotubes (BN-CNTs) have attracted considerable attention in recent research. In this effort, molecular dynamics simulations were performed to study the fundamentals of BN-CNTs in tensile tests, i.e. Young’s modulus and fracture strength (strain). Particular attention was paid to the influence of the atomic structure, hybrid style, and BN concentration on the tensile properties. The morphological changes were also investigated for the BN-CNTs at the onset of fracture. It is noted that the Young’s modulus of BN-CNTs decreases almost linearly with increasing the BN concentration with a rate of change independent of the hybrid style. In contrast, the sensitivity of the fracture strength and fracture strain to the variation of BN concentration depends strongly on the hybrid style of BN-CNTs. These results are expected to significantly expand the knowledge of the elastic and fracture properties of novel nanostructures and facilitate their applications in bandgap-engineering.

Composition-dependent buckling behaviour of hybrid boron nitride-carbon nanotubes.

The buckling of hybrid boron nitride-carbon nanotubes (BN-CNTs) with various BN compositions and locations of the BN domain is investigated using molecular dynamics. We find that BN-CNTs with large BN composition (>38%) only undergo local shell-like buckling in their BN domain. Although similar local shell-like buckling can occur in BN-CNTs with a relatively small BN composition, it can transfer to the global column-like buckling of the whole BN-CNT with increasing strains. The critical strains for local shell-like and global column-like buckling decrease with increasing BN composition. In addition, critical strains and buckling modes of the global column-like buckling of BN-CNTs also strongly depend on the location of their BN domain. As a possible application of the buckling of BN-CNTs, we demonstrate that the BN-CNT can serve as a water channel integrated with a local natural valve using the local buckling of its BN domain.

Sensing single molecules with carbon–boron-nitride nanotubes

We investigate the molecular sensing properties of carbon nanotube–boron nitride–carbon nanotube (CNT–BN–CNT) junctions.