Armchair Boron Nitride Nanotubes Research Articles

A comparative simulation study of piezoelectric properties in zigzag and armchair boron nitride nanotubes: by discovering a pioneering protocol

A comparative simulation study of piezoelectric properties in zigzag and armchair boron nitride nanotubes: by discovering a pioneering protocol

Analyze the temperature-dependent elastic properties of single-walled boron nitride nanotubes by a modified energy method

The elastic properties of boron nitride nanotubes (BNNTs) were investigated utilizing an enhanced energy method. By considering small deformations and applying the principle of minimum potential energy, the variations in atomic bonds and bond angles within the nanotube structure were determined. The modified model incorporated the contribution of inversion energy to the overall potential energy of the system, leading to the derivation of analytical expressions for the Young's modulus, shear modulus, and strain energy of both armchair and zigzag BNNTs under varying temperatures. The results indicate that compared to zigzag BNNTs, the impact of inversion energy on the elastic constants of armchair BNNTs is more significant, especially at small diameters (<1 nm). In thermal environment, this study demonstrates that the change in Young's modulus of BNNTs is lower than that of carbon nanotubes (CNTs), confirming the superior thermal stability of BNNTs over CNTs. Furthermore, molecular structure mechanics (MSM) and continuum mechanics models were employed to analyze the strain energy of BNNTs. The effects of different bonds, bond angles, and inversion angles on strain energy were analyzed in a thermal environment, revealing distinct differences between the two types of BNNTs. These findings provide more accurate theoretical guidance for thermal applications based on the stretching of BNNTs.

Deformation behaviors of hydrogen filled boron nitride and boron nitride - carbon nanotubes: Molecular dynamics simulations of proposed materials for hydrogen storage, gas sensing, and radiation shielding

Boron nitride nanotubes (BNNTs) have been extensively studied for hydrogen storage, sensing, and radiation shielding applications. The deformation behaviors of pristine, defective, and H2-encapsulated closed-end armchair BNNTs and BNNT-carbon nanotube (CNT) heterostructures are investigated using molecular dynamics employing the ReaxFF interatomic potential and a combination of Tersoff, adaptive intermolecular reactive empirical bond order, and Lennard-Jones potentials. The calculated elastic properties for pristine BNNTs and CNTs are in excellent agreement with published reliable data. The nanotube length and diameter, defects, entrapped hydrogen content, and temperature all affect the mechanical properties significantly. The ReaxFF potential predicts H2 molecule adsorption on B atoms of undeformed BNNTs whilst under strain, the H2 molecules show preference for the N atoms. Hydrogen adsorption leads to lowering of the elastic and fracture strength of BNNTs. The ReaxFF potential is shown to be a reliable forcefield for investigating the interaction of H2 molecules with BNNTs and BNNT-CNT heterotubes.

Evaluating the elastic behaviour of boron nitride nanotube (BNNT) reinforced phenolic nanocomposites

The present analysis concerns investigation of the elastic behavior of boron nitride nanotube (BNNT)-reinforced phenolic nanocomposite using molecular dynamics (MD) simulations. In the investigation, an armchair BNNT with chiral vectors (10, 10) was used as reinforcement and novolac-type phenolic chains and formaldehyde mixture was used as a matrix. The crosslinking of phenolic chains and formaldehyde mixture was achieved to obtain the three-dimensional crosslinked structure reinforced with BNNT. In addition to the tensile elastic modulus, the glass transition temperature was evaluated for the bulk phenolic resin and the nanocomposite using the density-temperature relationship. Based on the results, it was concluded that 6.8% (volume fraction) of BNNT can enhance the elastic modulus of the composite by ∼15 times. Poisson’s ratio was found to be independent of the mixing ratio. It was also observed that reinforcement with BNNT can enhance the glass transition temperature of the nanocomposite. Continuum-based rule of mixture showed a good correlation with the MD predictions.

Engineering and controlling the electronic properties of zigzag and armchair boron nitride nanotubes with various concentrations of oxygen impurities

This research underscored the comprehension of the electronic properties of the various diameters for zigzag and armchair single-wall boron nitride (ZSWBNNTs and ASWBNNTs) under various concentrations of oxygen impurities. The electronic properties of these tubes are investigated by using the first density functional theory (DFT), which implemented in the QUANTUM ESPRESSO package. Results show that the electronic properties of all these tubes can be controlled by using different concentrations of oxygen impurities. In the pristine case, the electronic band gap of these tubes is deepened on the diameter. So, the electronic band gap is increased by increasing the diameter of the tube. Nevertheless, these properties are changed and affected by various concentrations of oxygen impurities. The electronic band gap of ZSWBNNTs reduced by using one and two -hexagonal of oxygen impurities, and the behavior of ASWBNNTs changed from insulator to semiconductor properties by using a 2-hexagonal of oxygen impurities. Our investigation revealed for the first time that the behaviors of ZSWBNNTs and ASWBNNTs are changed from semiconductor and insulator to metallic with seven oxygen impurities. Then, there are very fascinating results. Also, the electronic band gap doesn't only depend on the impurity concentration, but also depends on the geometrical pattern of oxygen impurities in the ASWBNNTs.

Quantum Chemical Approaches to the Encapsulation of Parathion, Chlorpyrifos and Coumaphos by Armchair and Zigzag Boron Nitride Nanotubes Doped with Aluminum

Boron nitride nanotubes have been widely used as drug delivery vehicles and for the controlled release of targeted therapeutic drugs. In this study, we calculated the encapsulation efficiencies of three organophosphorus pesticides, parathion, chlorpyrifos, and coumaphous, using quantum chemical methods. The results show that the encapsulation energy of zigzag BNNT(20,0) is lower than that of armchair BNNT(12,12) to encapsulate parathion. Al doping helps to decrease the encapsulation energy and Al-doped zigzag BNNT(20,0) + parathion has the greatest binding affinity. In addition, the energy gap of armchair BNNT(12,12) encapsulating organophosphorus pesticides changed significantly. Al doping reduces the band gap of boron nitride nanotubes. Al-doped armchair BNNT(12,12) has the strongest electron-accepting ability and is a promising sensor material.

Quantum DFT methods to explore the interaction of 1-Adamantylamine with pristine, and P, As, Al, and Ga doped BN nanotubes

Nanostructures, nowadays, found growing applications in different scientific and industrial areas. Nano-coins, nanosheets, and nanotubes are used in medical applications as sensors or drug delivery substances. The aim of this study is to explore the adsorption of 1-Adamantylamine drug on the pristine armchair boron nitride nanotubes (BNNTs) with BNNT(5,5), BNNT(6,6), and BNNT(7,7) chirality along with the P, As, Al and Ga-doped BNNTs, using the quantum mechanical density functional methods. Considering the fact that dispersion effects are important in the case of weak Van der Waals interactions, computations have been done using B3LYP hybrid functional with the implementation of the D3(BJ) empirical dispersion correction methods. Quantum theory of atoms in molecules, natural bonding orbitals, and Kohn–Sham orbitals were used to investigate the nature and type of the adsorption process. The results showed that, while the adsorption of 1-Adamantylamine on the outer surface of pristine BNNT is physical in nature, doping can improve the ability of detracted BN to adsorb the drug through chemical bonds. Also, it was found that, by increasing the radius of the BNNT the adsorption energy was decreased. In conclusion, results of the present work suggest that, Ga doped nanotube, due the chemisorption, is not an ideal nanotube in drug delivery of 1-Adamantylamine drug, whereas, the other studied cases physiosorbed the drug, and may not have serious problem in release of the 1-Adamantylamine drug.

Density Functional Theory-Based Studies Predict Carbon Nanotubes as Effective Mycolactone Inhibitors

Fullerenes, boron nitride nanotubes (BNNTs), and carbon nanotubes (CNTs) have all been extensively explored for biomedical purposes. This work describes the use of BNNTs and CNTs as mycolactone inhibitors. Density functional theory (DFT) has been used to investigate the chemical properties and interaction mechanisms of mycolactone with armchair BNNTs (5,5) and armchair CNTs (5,5). By examining the optimized structure and interaction energy, the intermolecular interactions between mycolactone and nanotubes were investigated. The findings indicate that mycolactone can be physically adsorbed on armchair CNTs in a stable condition, implying that armchair CNTs can be potential inhibitors of mycolactone. According to DOS plots and HOMO–LUMO orbital studies, the electronic characteristics of pure CNTs are not modified following mycolactone adsorption on the nanotubes. Because of mycolactone’s large π-π interactions with CNTs, the estimated interaction energies indicate that mycolactone adsorption on CNTs is preferable to that on BNNTs. CNTs can be explored as potentially excellent inhibitors of mycolactone toxins in biological systems.

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.

Electronic and optical properties of ultra-small diameter armchair carbon and boron nitride nanotubes by PBE, TB-mBJ and YS-PBE0 functionals

We have investigated the electronic and optical properties of ultra-small (3,3), (4,4) and (5,5) armchair single walled nanotubes carbon (C-SWNTs) and boron nitride (BN-SWNTs) using three density functional methods of different categories, namely, PBE, TB-mBJ and hybrid functional YS-PBE0. A density functional theory (DFT) within the full-potential linearized augmented-plane wave (FP-LAPW) method, was used to study the structures, electronic and optical properties of these nanotubes. The calculation of optical properties has been performed under electric fields polarized both parallel and perpendicular with respect to the nanotube axis. The results show that the hybrid functional YS-PBE0 perform the best for calculations of band gap of BN-SWNTs (5.27–5.54 eV), while for C-SWNTs the PBE and TB-mBJ functionals obtain band gap range (0.16–0.28 eV) with smaller errors compared to experimental values and confirming the semiconducting behavior of the studied C-SWNTs. The dielectric function is anisotropic for all tubes and is larger in the parallel direction. The results show also that for C-SWNTs, the static refractive index is higher than those of BN-SWNTs and it has an inverse correlation with the C-SWNTs diameter. This proves that for optoelectronic applications, it is improve to use the BN-SWNTs doped than intrinsic.

Boron Nitride Nanotubes for Curcumin Delivery as an Anticancer Drug: A DFT Investigation

The electrical properties and characteristics of the armchair boron nitride nanotube (BNNT) that interacts with the curcumin molecule as an anticancer drug were studied using ab initio calculations based on density functional theory (DFT). In this study, a (5,5) armchair BNNT was employed, and two different interactions were investigated, including the interaction of the curcumin molecule with the outer and inner surfaces of the BNNT. The adsorption of curcumin molecules on the investigated BNNT inside the surface is a more favorable process than adsorption on the outside surface, and the more persistent and stronger connection correlates with curcumin molecule adsorption in this case. Furthermore, analysis of the HOMO–LUMO gap after the adsorption process showed that the HOMO value increased marginally while the LUMO value decreased dramatically in the curcumin-BNNT complexes. As a result, the energy gaps between HOMO and LUMO (Eg) are narrowed, emphasizing the stronger intermolecular bonds. As a result, BNNTs can be employed as a drug carrier in biological systems to transport curcumin, an anticancer medication, and thereby improve its bioavailability.

A two-section beam element to model the B-N covalent bonds in boron nitride nanotubes

The ability of molecular mechanics to model the covalent bonds with equivalent elements is limited to the bonds connected with similar atom pairs. When dissimilar atoms are connected by covalent bonds, single-sectioned beam or spring elements could not capture the physical properties of the bond. In this respect, a molecular mechanics based two-sectioned beam element was formulated based on strain energy minimization and was used to model the elastic and vibrational characteristics of the boron nitride nanotubes (BNNT). Inconsistent conclusions given by the conventional molecular mechanics models were all rectified by the present formulation. It was shown that the armchair BNNTs has higher Young's modulus than that of zigzag counterparts. This was captured by the model with two-section beam elements, while single-section beam and equivalent spring elements are unable to predict this conclusion. The shear modulus of the zigzag BNNTs were 10 to 17 percent higher than the armchair counterparts.

Theoretical investigation on 5–fluorouracil anti–cancer drug adsorption on Sc– and Ti–doped armchair and zigzag boron nitride nanotubes

The application of nanomaterials as a drug delivery system for anticancer is now becoming an important for control drug release near the tumor cell. Herein, the adsorption properties of 5–fluorouracil (5FU) drug on pristine armchair and zigzag single wall boron nitride nanotubes (BNNT) and their doping with Sc or Ti atom in gas phase and water solution conditions were investigated through density functional theory calculations. The interactions of 5FU molecule and BNNTs on the geometrical stabilities, adsorption abilities and electronic properties were also determined and discussed. The calculations reveal that there are shorter adsorption distance, higher adsorption ability, higher solubilities, and larger charge transfer when 5FU molecule is adsorbed on Sc– and Ti–doped BNNTs in comparison with adsorptions on pristine BNNT. According to the results, the doping of transition metal atom is improved the reactivity of BNNTs toward 5FU molecule. Thermodynamic analyses demonstrate that interactions between 5FU molecule and Sc– and Ti–doped BNNTs are exothermic and spontaneous processes. The recovery time is attained to be 272.63 s for the 5FU desorption from the Ti doping on N site of armchair BNNT. The electronic properties reveal that after 5FU adsorption, the energy gap and density of state of Sc– and Ti–doped BNNTs are clearly changed than that of pristine BNNT, which suggests that Sc and Ti doping is improved the sensitivity of BNNTs to 5FU molecule. Therefore, Sc– and Ti–doped BNNTs can be a good candidate for sensors or catalyst to adsorb and detect 5FU molecule for drug delivery system in the nanomedicine domain.

Potential applications of armchair, zigzag, and chiral boron nitride nanotubes as a drug delivery system: Letrozole anticancer drug encapsulation

A density functional theory calculation has been applied to be investigated the ability of (12,12) armchair, (21,0) zigzag, and (18,5) chiral boron nitride nanotubes (BNNT) as the drug nanocarrier in Letrozole delivery. For this purpose, the behavior of drug Letrozole when encapsulated into different chirality of BNNTs with the same diameter was studied. Moreover, the reduced side effects and increasing solubility of Letrozole can be achieved by encapsulation in boron nitride nanotubes. A complete understanding of the encapsulation process of drug molecules into BNNTs is necessary for the development of drug delivery systems. Geometry optimizations of the three types of BNNTs and drug Letrozole have been performed by means of density functional theory calculation, using the functional wb97xd with 6-31G basis set. The results indicate that Letrozole is encapsulated in cavity of the nanotubes. The structural and the electronic properties of encapsulated Letrozole in the studied systems have been also predicted by quantum mechanical descriptors such as equilibrium distances, highest occupied molecular orbital (HOMO)—lowest unoccupied molecular orbital (LUMO) energy gap. The quantum mechanical calculations verify that the armchair and the chiral single-walled boron nitride nanotubes could spontaneously adsorb Letrozole in a chemisorption process while the physisorption process plays a large role in adsorption within the zigzag single-walled boron nitride nanotube.

Sensing capability and diameter-dependent electronic structure of boron nitride nanotubes

The sensing and diameter-dependent properties of armchair Boron Nitride nanotubes (BNNTs) were scrutinized based on density functional theory (DFT) to find out their electronic structure and carbon monoxide (CO) sensing capability. Our results show that diameter increase causes a rise in the binding energy of BNNT, from 6.44 eV to 6.62 eV. An increasing trend of adsorption energies in the range of -3.25 and -3.47 kcal/mol indicates that BNNTs act weak physical adsorption upon CO verified by the analysis of the Electron localization function (ELF), however, more increase in the diameter could enhance the sensing capability of BNNT. The energy gap of the biggest BNNT is calculated as 6.20 eV wide, i.e., about 0.12 eV smaller than the smallest one which is compatible with available experimental results. The reactivity properties such as the adiabatic and vertical ionization potentials (IPs), chemical hardness, and electrophilicity index of BNNTs were also analyzed. The BNNTs exhibit strong absorption peaks ∼7.08 eV which can be a promising candidate for the UV light-emitting devices. The results herein reveal that BNNTs with bigger diameters can be useful for gas sensor applications.

Molecular dynamics simulation of separation of water/methanol and water/ethanol mixture using boron nitride nanotubes

The efficient separation of methanol and ethanol from water is an important issue due to the applications of these alcohols in many fields. This is a molecular dynamics simulation study of water/methanol and water/ethanol mixtures separations using four different types of armchair boron nitride nanotube (BNNT) including (7,7), (10,10), (12,12), and (13,13) BNNTs. The radial distribution function of solvents, density profile of solvent molecules, and number of hydrogen bonds between molecules were investigated to study the structural and dynamical properties of molecules inside the BNNTs and also, in the feed and permeate sides of the simulation box. Under a concentration gradient, (10,10) BNNT and (13,13) BNNT could selectively separate methanol and ethanol molecules from water molecules, respectively. BNNTs diameter sizes, hydrogen bonding between solvent molecules, and Van der Waals interactions between solvent molecules and BNNT were influential factors on the selective separation of methanol and ethanol molecules from water. Furthermore, the influence of applied hydrostatic pressure and electric field on the permeation of solvent molecules through BNNTs was investigated. It was revealed that these external applied forces were effective in the passage of molecules through BNNT in comparison to when applied hydrostatic pressure and electric field were absent.

Hybrid approach for dynamic analysis of single-walled Boron Nitride Nanotube (SW-BNNT) in presence of vacancy defect

The appropriateness of single walled Boron Nitride Nanotube for recognition of mass as little as of the request for femtogram level (10–18 fg) in nearness of centre found point defect has been investigated through current paper using 3-dimensional atomistic structure approach based on finite element method. The impact of shifting mass in nearness of defect on frequency for armchair (5,5) Boron Nitride Nanotube has been analysed for bridge setup.Considering FEM approach the mass affectability for bridge design is seen as higher when contrasted with cantilever one. The experimental results delight that shorter length of BNNT with bridge arrangement is appropriate for detecting mass as little as of the request for femtogram level when mass is available on focus.

Density functional theory study of Cu-doped BNNT as highly sensitive and selective gas sensor for carbon monoxide

The adsorption of CO, CO2, CH4, H2, N2 and N2O on armchair (5,5) boron nitride nanotube (BNNT) with and without the doping of transition metals (TM), i.e. Sc, Ti, V, Cr, Mn, Fe, Co, Ni, Cu or Zn, was investigated using the density functional theory calculation. The results indicate all the considered gases are physically adsorbed by weak interaction on the pure BNNT, revealing that pure BNNT has poor sensing performance for these gases. TM are then doped in the B or N vacancy of BNNT to improve the sensitivity and selectivity. As a result, it was found that the gas adsorption performance of BNNT is obviously enhanced due to the introduction of TM dopant atom. In particularly, according to the results of adsorption energy, Cu doped BNNT (Cu-BNNT) system shows a high selectivity toward CO molecule compared with other metal doped systems. This is further confirmed by the density of state, energy gap and charge transfer analyses. Furthermore, based on the sensor performance analysis, it was found that Cu-BNNT also has favorable desorption characteristics for CO. Therefore, this study concluded that Cu-BNNT can be used as a superior sensor material with high sensitivity, selectivity and favorable recycle time for CO gas.

Electric Field Effects on Buckling Analysis of Boron–Nitride Nanotubes Using Surface Elasticity Theory

In this paper, the axial buckling of boron nitride nanotubes (BNNTs) is investigated by considering the effects of surface and electric field. To achieve this purpose, the surface elasticity theory is exploited and the results are compared with the molecular dynamic simulation in order to validate the accuracy of the applied theory. In the molecular dynamics simulation, the potential between boron and nitride atoms is considered as Tersoff type. The Timoshenko beam theory is adopted to model BNNT. Moreover, two types of zigzag and armchair BNNTs are considered. In this study, the effects of surface, electric field, length, and thickness of BNNT on the critical buckling load are investigated. According to the results, the critical load of zigzag BNNT depends on the electric field. However, the electric field would not affect the critical load of the armchair BNNT. It should be noted that the surface residual tension and surface Lamé’s constants of BNNT have considerable impact on the critical load of BNNT. For lower values of electric field and smaller dimensions of BNNT, the critical load would be more dependent on the surface effect regarding the results. Furthermore, as an efficient non-classical continuum mechanic approach, the surface elasticity theory can fill the potential gap between the classical continuum mechanic and molecular dynamics simulation.

Plasmonic excitations and charge structure factor in armchair boron nitride nanotubes

In this paper we investigated theoretically both dynamical and static charge susceptibilities of armchair Boron-Nitride nanotube(BNNT). Using the imaginary part of the dynamical charge susceptibility function, one can find the plasmonic modes of the system. For this purpose we implement Green's function approach in the context of the tight-binding model hamiltonian. According to linear response theory the charge response function will be obtained via calculating the correlation function of charge density-density operators. Also we present the static charge structure factor which can be a criterion for charge ordering of the system. Especially the effect of gap parameter and chemical potential on the plasmon modes and static charge structure factor of armchair BNNT are investigated. Our results show that the chemical potential changes the number of plasmon modes and their positions. Furthermore chemical potential and gap parameter affect on the static charge susceptibility and consequently charge ordering of the BNNT is changed. • The investigation of charge structure factors of armchair nanotubes. • The study of chemical potential and gap parameter on dynamical susceptibility of nanotube. • The investigation of static structure factor behavior as a function of temperature.