Boron Nitride Research Articles

Maximizing filler content and manufacturing highly thermal conductive composite materials through eutectic liquefaction of epoxy resin

We report novel research results demonstrating the production of polymer nanocomposites with high thermal conductivity. The use of diluents, a conventionally used method to reduce viscosity and increase processability, had clear limitations that could not be used for solid epoxy, but in this study, the melting point of the epoxy itself was reduced through the introduction of the eutectic system, allowing the solid epoxy to be converted into a liquid phase. By utilizing eutectic liquid (EL) derived from ketone-containing epoxy resin (DBPE) and diphenylamine (DPA), we achieved maximal filler content. Unlike DBPE’s solid form at 135 °C, EL displayed liquidity with a viscosity of 50 Pa·s at 50 °C, enabling curing with isophorone diamine (IPDA) below DBPE’s melting point. While DBPE/IPDA yielded a tensile strength of 7.2 MPa due to uneven mixing, EL/IPDA reached 44.3 MPa, marking a 520 % improvement. EL’s viscosity dropped dramatically, reaching 0.06 Pa·s at 98 °C. The EL/IPDA mixture’s viscosity at 98 °C was 150 Pa·s, allowing up to 80 wt% hexagonal boron nitride (h-BN) filler. This led to a thermal conductivity of 16 W/m·K, 20 wt% higher than DGEBA’s 60 wt% filling rate. Notably, EL/h-BN composites achieved 16 times the thermal conductivity of DGEBA/h-BN composites, which is 1 W/m·K. Lowering the melting point and viscosity expanded curing agent choices, enhanced tensile strength, increased filler content, and heightened thermal conductivity, showcasing EL’s remarkable potential.

Enhanced piezoelectricity of P(VDF-TrFE) by BN nanosheets doping and leading to high performance laminated magnetoelectric composites

With the development trend of miniaturization, lightweight and portability of electronic equipment, piezoelectric devices have been widely applied to transducers, sensors and energy harvesters. Piezoelectric polymers, like poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)), possess the advantages of light weight, good flexibility, and simple preparation methods. However, P(VDF-TrFE) films is not entirely composed of piezoelectric phase (β phase), so increasing the content of β-phase is very important for the piezoelectric property of P(VDF-TrFE) films. Doping nanomaterials with unique properties has been proved to be a feasible way to increase the content of β-phase. In this paper, hexagonal boron nitride (h-BN) nanosheets, a kind of 2-dimensional van der Waals materials with wide bandgap, as filler were doping into poly(vinylidene fluoride-trifluoroethylene) (P(VDF-TrFE)) piezoelectric films by solution casting method. The composite films as designed, in which h-BN nanosheets were uniformly dispersed in P(VDF-TrFE), achieved higher contents of piezoelectric phase (β phase). Compared with pure P(VDF-TrFE) films, the optimal P(VDF-TrFE)/BN piezoelectric film achieved a much higher piezoelectric coefficient (d33) (∼42 pC/N), also leading to a higher piezoelectric voltage output than that of pure P(VDF-TrFE). By laminating the P(VDF-TrFE)/BN films as designed with FeSiB Metglas, high magnetoelectric voltage coefficients under zero and low DC magnetic bias were achieved. In summary, this paper presents a feasible and potential method for improving PVDF piezoelectricity, which has been successfully applied in high performance magnetoelectric devices.

A bi-layer superhydrophobic coating with long-term anti-corrosion enabled by functionalized hexagonal boron nitride and PDMS-based polyurethane on Mg alloy

Two-dimensional (2D) nanocomposite coatings and superhydrophobic coatings are applied to retarding corrosion of Magnesium (Mg) and its alloys. However, stability of the delicate micro/nanostructure and corrosion durability are still intractable issues. In this work, a bi-layer superhydrophobic coating with excellent corrosion resistance has been successfully constructed on Mg alloy via a facile spray/spin assisted self-assembly technique. The polyurethane (PU) coating containing well-dispersed hydroxylated hexagonal boron nitride (OH-BN) nanoparticles acts as the barrier layer and “adhesive”, while the superhydrophobic modified h-BN (f-BN) nanoparticles serve as the water-repellent surface. In addition, the modifying agents containing dynamic disulfide bonds provide covalent bonding effect to construct a stable superhydrophobic surface. Hence, the obtained coating presents extreme non-wettability with an impressive static water contact angle (WCA) of 155° as well as possesses outstanding anti-water adhesion, anti-fouling and self-cleaning performance. Meanwhile, the designed coating shows excellent corrosion durability, which the value of |Z|f=0.01 Hz retains at 9.5 × 109 ohm cm2, higher than PU coating of two orders of magnitude. The developed coating shows promising potentials as a durable protective material for Mg alloy and other metals and alloys, shedding new lights on developing high-performance corrosion resistance technologies.

Epoxy Composite Films Filled with Sintered Multifaceted Boron Nitride for Thermal and Dielectric Applications

The miniaturization of electronic devices has led to an increase in power density and functional integration, resulting in rapid heat accumulation that adversely affects operational stability and service life. Dielectric composite films with excellent thermal conductivity and insulating properties are highly desired for addressing thermal management issues in electronic packaging applications. Hexagonal boron nitride (h-BN) is a promising filler for such composites due to its outstanding thermal conductivity, insulating properties, and chemical stability. However, the inherent platelike structure of h-BN causes significant anisotropy and poor miscibility with polymers, limiting the uniform conduction of heat. This study proposes a high-temperature sintering method that transforms flaky h-BN plates into irregular multifaceted particles. This transformation reduces thermal anisotropy and creates uniform heat conduction pathways. The resulting sintered BN/Epoxy (s-BN/EP) composite films exhibit exceptional thermal conductivity, with in-plane thermal conductivity increased by 36% to 6.0 W m-1 K-1 and through-plane thermal conductivity increased by 39% to 1.2 W m-1 K-1 compared to pristine h-BN/epoxy composites. Moreover, s-BN/EP films could maintain low dielectric constant (Dk, 3.22) and dielectric loss (Df, 0.015) at 5 GHz. This innovative approach provides a significant advancement in the development of high-performance insulating polymer composites, offering a promising solution for thermal management in high-power-density electronic packaging.

Reactive extrusion for efficient preparation of high temperature resistant PA6T/66/BN composites with great thermal management and mechanical properties

High temperature resistant polymer-based composite with high thermal conductivity and great mechanical properties are highly demanded in the field of electronic devices for simultaneously meeting surface mounting process and high-power operation. The key to achieving this goal is to balance the contradiction between the high melt viscosity of high-temperature resistant polymers and the dispersibility of fillers. In this work, the high-performance polyamide 6T/66/hexagonal boron nitride (PA6T/66/BN) composites were fabricated successfully via the method combining prepolymerization and reactive extrusion. Results demonstrated that this method not only significantly improves the preparation efficiency of high temperature resistant polyamide and its composites, but also enables the prepared composites to reach 3.6 W/(m⋅K), over 299 °C and 67.8 MPa in thermal conductivity, melting point and tensile strength respectively. Furthermore, the prepared composite exhibits excellent thermal management effects on LED and CPU. Therefore, the results of this work are of great significance for the efficient preparation and wide application of high-temperature resistant polymer based thermally conductive composites.

Fabrication of advanced polyphenylene sulfide composites by in-situ grafting of sulfide silane and PCPA on glass fibers

The energy crisis has driven increased adoption of electric vehicles (EVs) in the automotive sector, with a focus on lightweight engineering plastics (EPs) for fuel efficiency. This study aims to enhance the mechanical properties and thermal conductivity of EPs to address heat-related concerns in EVs and electronic devices. A hybrid filler (milled glass fiber, boron nitride, and graphene oxide) was introduced to polyphenylene sulfide (PPS), using a simultaneous grafting process with poly(catechol/polyamine) (PCPA) and silane additives. Filler aggregation in the resin matrix was overcome with surface-treatment agents such as Bis[3-(triethoxysilyl)propyl] tetrasulfide (Si69), catechol, and tetraethylenepentamine. PCPA polymerization on the filler surfaces bridged connections between fillers and silane molecules. The resulting surface-treated hybrid composite showed a 637% increase in thermal conductivity (2.102 Wm−1K−1) and a 63.94% increase in tensile strength (65.87 MPa) compared to the base matrix. Incorporating 40 wt.% surface-treated mGF, 30wt.% raw BN, and 6wt.% surface-treated GO, along with PCPA and Si69 treatments, achieved this improvement. The hybrid filler composites significantly enhanced thermal conductivity and mechanical properties, providing a rapid and convenient solution to challenges in robustness and heat dissipation for electronic vehicles and devices.

Maximizing Methane and Hydrogen Delivery Capacity by Carbon and Boron Nitride Nanoscrolls

The CH4 and H2 delivery capacity of carbon and boron nitride (BN) nanoscrolls was investigated, with a focus on optimizing the interlayer and van der Waals spacings to meet the U.S. Department of Energy (DOE) targets. Through computational simulations, the effects of interlayer spacing on CH4 and H2 adsorption were evaluated, revealing that while delivery quantities increase with interlayer spacing, achieving DOE targets remains a challenge for CH4. Notably, BN nanoscrolls exhibited higher adsorption capacities compared to carbon nanoscrolls, especially under low-pressure conditions. Conversely, carbon nanoscrolls displayed greater release quantities than BN nanoscrolls. For H2, delivery quantities met DOE targets at larger interlayer spacings, with carbon nanoscrolls requiring a spacing greater than 0.9 nm and BN nanoscrolls greater than 1.1 nm. For CH4 delivery, temperature optimization showed significant peaks in delivery for carbon nanoscrolls at 248 K. In contrast, BN nanoscrolls did not exhibit a peak in delivery. In carbon nanoscrolls, the optimal weight and volumetric capacities for methane delivery are 0.275 g/g and 182 cm3/cm3, respectively. Meanwhile, for hydrogen, the maximum delivery achieved is 8.26 wt% and 0.044 kg/L, which surpasses the DOE’s storage target of 5.5 wt% and 0.04 kg/L. The study also highlighted the importance of structural parameter optimization, with a significant increase in weight delivery (>500%) and in volume delivery (>120%) for both gases.

Effect of filler loading on the frictional, thermal and mechanical properties of ABS/boron nitride (h-BN) nanocomposites

The effect of hexagonal boron nitride (h-BN) nanoparticles in acrylonitrile butadiene styrene (ABS) polymer matrix is investigated. ABS/h-BN nanocomposites were prepared with h-BN content ranging from 0.5 to 5 wt% and their frictional, thermal and mechanical properties were evaluated. XRD analysis showed that the 'd' spacing in h-BN stacks increased in the ABS nanocomposite due to the interpenetration of ABS polymer chains. The tensile properties and thermal stability of ABS matrix showed better improvement with 0.5 wt% addition of h-BN nanoparticles. The tensile fracture mechanism in ABS/h-BN nanocomposites was predicted using tensile fracture surface analysis. Coats-Redfern approach was applied to support the thermal stability analysis results. Significant enhancement (28 %) in frictional property of ABS was observed in the nanocomposite with h-BN. Wettability and flame retardancy of the ABS/h-BN nanocomposites were also investigated.

Charge Capturing Effects of Boron Nitride Nanosheets on Enhanced Triboelectric Properties of Polyimide Nanocomposite Films in a Conductor-to-Dielectric Mode

Dielectric composite materials play a crucial role in the performance of triboelectric nanogenerators (TENGs) by influencing charge storage and transfer capabilities. In this study, we investigate the influence of boron nitride nanosheets (BNNS) on the triboelectric properties of polyimide (PI)-based dielectric nanocomposite films within a TENG setup employing a conductor-to-dielectric configuration and a contact-separation mode. To achieve this, we manufactured PI/BNNS nanocomposite films containing 1-10wt% BNNS with a thickness of ~14.67nm via a solution casting method, followed by thermal imidization. Thermogravimetric characterization revealed that the thermal stability of the nanocomposites improved with increasing BNNS content. Additionally, the triboelectric performance of the PI/BNNS films, used as the negative friction layer, was enhanced due to the electron-trapping capabilities at the BNNS-PI interface. Among the samples, the nanocomposite film containing 5wt% BNNS exhibited the most significant triboelectric output, generating a voltage of ~4.0V and a current of ~426.4nA. Moreover, the triboelectric AC output generated by the TENG using PI/BNNS nanocomposite films was successfully rectified into DC signals and subsequently stored in microcapacitors. This capability highlights the significant potential of PI/BNNS nanocomposite films for energy harvesting and storage applications, further supporting their suitability for integration into advanced flexible energy devices.

Enhanced strength and ductility of boron nitride nanosheet reinforced cu composites through constructing an interfacial three-dimensional structure

To address the poor wettability and weak interface bonding between boron nitride nanosheet (BNNS) and Cu, BNNS/CuTi composites were prepared through matrix microalloying by adding 1 wt% Ti. Solid-state interfacial reactions resulted in the formation of TiN transition layers and TiB whiskers (TiBw), collectively constructed a BNNS-(TiN&TiB)-Cu interfacial three-dimensional structure (I-3DS). The coherent I-3DS significantly reduced the interfacial energy, improved the interfacial stability, and achieved a favorable combination of strength and ductility in BNNS/CuTi composites. The 0.1 wt% BNNS/CuTi composite achieved an ultimate tensile strength (UTS) of 485 MPa, representing increases of 114 % and 62 % over pure Cu and 0.1 wt% BNNS/Cu composite, respectively. The interlocking structure formed by I-3DS and Cu doubled the theoretical interface shear strength limit and improved load transfer efficiency. This study offered new insights into the innovative design of high-performance Cu matrix composites (CMCs) by constructing I-3DS.

Magnetic field dependence of $V_B^-$ defects in hexagonal boron nitride

Magnetic field dependence of $V_B^-$ defects in hexagonal boron nitride

Scalable approach for growing hexagonal boron nitride on silicon and its role in III-nitride van der Waals epitaxy

Hexagonal boron nitride (h-BN) stands out among 2D materials for its insulating properties, making it promising for the integration of 2D and 3D materials. However, achieving wafer-scale growth on silicon substrates remains a significant challenge. In this study, growth strategies for depositing h-BN on Si substrates are explored utilizing the wafer scalable metalorganic chemical vapor deposition. Our investigations reveal that employing a pulsed flow mode scheme is preferable over the conventional continuous flow mode scheme in growing h-BN thin films on 150 mm Si substrates. The as-grown h-BN film on Si exhibits uniform coverage with h-BN[0001]//Si[111]. With the successful wafer-scale growth of h-BN on Si, its role in aiding the van der Waals epitaxy of III-nitrides on Si substrates and subsequent epitaxial lift-off (ELO) of III-nitrides is further exemplified. An optimized h-BN thickness for the ELO process is also determined.

Boron nitride nanotubes as carriers of genistein for multitherapeutic cancer treatment: A DFT study of electronic and solubility properties

Increasing cancer mortality statistics demand more accurate and efficient treatments. Nanostructures have proved to be promising choices in this regard. Nanotubes with large surface areas can play multiple roles from drug carriers in targeted drug delivery to beam absorbers in the photothermal method. While carbon nanotubes (CNTs) show cytotoxicity, Boron Nitride Nanotubes (BNNTs) offer wide bandgap and biocompatibility. In this study, we investigate the electronic and solvation properties of (5,5), (6,6), and (7,7) BNNTs computationally by the density functional theory. For multimodal therapy, we considered Iron (Fe) doping in the BNNT, which can be helpful in hyperthermia due to the magnetic moment of Fe. Our results show that doping has improved the band positions. Furthermore, we implemented an organic anticancer molecule, genistein, a metastasis inhibitor. All potent configurations connecting genistein with BNNT covalently demonstrated enhanced water solubility as compared to pristine and Fe-doped BNNTs. The results suggest that the (7,7) C3 complex is the most stable structure and the best drug carrier.

Generating Cationic Nickel Clusters over Oxygen-Functionalized Boron Nitride to Boost Methane Dry Reforming

Generating Cationic Nickel Clusters over Oxygen-Functionalized Boron Nitride to Boost Methane Dry Reforming

Single Electron Self-coherence and Its Wave/Particle Duality in the Electron Microscope.

Intensities in high-resolution phase-contrast images from electron microscopes build up discretely in time by detecting single electrons. A wave description of pulse-like coherent-inelastic interaction of an electron with matter implies a time-dependent coexistence of coherent partial waves. Their superposition forms a wave package by phase decoherence of 0.5 - 1 radian with Heisenbergs energy uncertainty ΔEH = ħ/2 Δt-1 matching the energy loss ΔE of a coherent-inelastic interaction and sets the interaction time Δt. In these circumstances, the product of Planck's constant and the speed of light hc is given by the product of the expression for temporal coherence λ2/Δλ and the energy loss ΔE. Experimentally, the self-coherence length was measured by detecting the energy-dependent localization of scattered, plane matter waves in surface proximity exploiting the Goos-Hänchen shift. Chromatic-aberration Cc-corrected electron microscopy on boron nitride (BN) proves that the coherent crystal illumination and phase contrast are lost if the self-coherence length shrinks below the size of the crystal unit cell at ΔE > 200 eV. In perspective, the interaction time of any matter wave compares with the lifetime of a virtual particle of any elemental interaction, suggesting the present concept of coherent-inelastic interactions of matter waves might be generalizable.

Thermal degradation of polytetrafluoroethylene, modified polytetrafluoroethylene, and their nanocomposites with boron nitride nanobarbs: Lifetime predictions and kinetic analysis

AbstractFlexible polymeric materials including dielectric thermal interface materials (TIMs) used in integrated circuits and other high frequency applications are exposed to extreme thermal and electrical conditions during their service life. Insight into the in‐use thermal stability and material lifetime is valuable to maintaining performance durability and preventing premature failure in actual end use. Herein, the thermal stability of polytetrafluoroethylene (PTFE), modified PTFE and their nanocomposites with recent generation boron nitride nanobarbs (BNNBs) was investigated based on lifetime prediction from thermogravimetric analysis and tensile strength deterioration of heat‐aged samples. Additionally, thermal degradation kinetics and mechanism was investigated using the model‐free advanced isoconversional method based on changing activation energy. The result shows that BNNB extends the lifetime of the PTFE by an order of magnitude. The degradation mechanism proposed from TGA‐MS result is supported by the multistep degradation mechanism identified in the kinetic computation. These results are valuable for predicting materials' in‐use lifetime to avoid premature failure.

Uncertainty analysis of MHD oscillatory flow of ternary nanofluids through a diverging channel: a comparative study of nanofluid composites

Purpose This study aims to investigate the heat and mass transfer characteristics of a temperature-sensitive ternary nanofluid in a porous medium with magnetic field and the Soret–Dufour effect through a tapered asymmetric channel. The ternary nanofluid consists of Boron Nitride Nanotubes (BNNT), silver (Ag) and copper (Cu) nanoparticles, with a focus on understanding the thermal behaviour and performance across mono, hybrid and tri-hybrid nanofluids. This paper also examines the thermal behaviour of MHD oscillatory nanofluid flow and carries out an uncertainty analysis of the model using the Taguchi method. Design/methodology/approach The governing equations for this system are transformed into coupled linear partial differential equations using non-similarity transformations and solved numerically with the Crank–Nicolson scheme. The impact of temperature sensitivity at three distinct temperatures (5°C, 20°C and 60°C) is incorporated to analyse variations in viscosity and Prandtl number. The study also examines the combined effects of Soret–Dufour numbers and thermal radiation on heat and mass transfer within the nanofluid. Findings The results demonstrate that the inclusion of BNNT, Ag and Cu nanoparticles significantly enhances heat and mass transfer rate, with copper nanoparticles showing superior performance in terms of skin friction and heat transfer rates. The Soret and Dufour effects play critical roles in modulating heat and mass diffusion within tri-hybrid nanofluids. The study reveals that temperature sensitivity alters heat and mass transfer characteristics depending on the temperature range, with pronounced variations at elevated temperatures. The influence of thermal radiation and the Peclet number is found to significantly impact temperature distribution and overall heat transfer performance within the asymmetric channel. Originality/value To the best of the authors’ knowledge, this study is the first to analyse the heat and mass diffusion in a ternary nanofluid composed of BNNT, Ag and Cu nanoparticles, considering porous media, oscillatory flow and thermal radiation within a tapered asymmetric channel. The research extends to a novel examination of temperature sensitivity in mono, hybrid and tri-hybrid nanofluids at varying temperature gradients. Furthermore, a comparative analysis of skin friction and heat transfer rates between copper, alumina and ferro composites is presented for optimising the nanofluid performance.

Template Quality Dependent Conversion Synthesis of Boron Nitride Coated Graphene Hybrid Aerogels for Ultrasensitive and Selective Ammonia Sensing

AbstractRecently, hexagonal boron nitride (h‐BN) nanomaterials, e.g., nanosheets and nanotubes, have been predicted to be effective materials for reversible gas adsorption with high selectivity once charged. However, despite the encouraging theoretical predictions, sensing with h‐BN is difficult to realize experimentally due to its electrically insulating nature stemming from its large band gap. In this research, the controlled synthesis of high surface area hybrid h‐BN/graphene aerogel is reported, using high‐quality graphene as a template, and its application for selective gas sensing. It is discovered for the first time in this system that the difficulty of conversion in template synthesis of h‐BN is positively correlated with the quality of the carbon template, an observation that is verified on both graphene nanosheets and carbon nanotubes. The application of this hybrid material for gas sensing yields ppb level of detection limit and high selectivity for NH3. Through density functional theory calculations, the adsorption energy and charge transfer between NH3 molecules and aerogel are greatly enhanced. Therefore, this innovative approach promises new possibilities for the application of h‐BN in gas sensing, with the potential to play a significant role in gas capture, environmental monitoring, and other related fields.

Noise reveals single defects in boron nitride

Noise reveals single defects in boron nitride

Flexible and Hierarchical Structured Alumina Boron Nitride Nanofibrous Aerogel for Thermal Superinsulation in Extreme Conditions

Flexible and Hierarchical Structured Alumina Boron Nitride Nanofibrous Aerogel for Thermal Superinsulation in Extreme Conditions