Search

Highlights m-BN/PNF nanocomposite paper with nacre-mimetic layered structures prepared via sol–gel film transformation approach presents excellent thermal conductivity, incredible electrical insulation, outstanding mechanical property and thermal stability. When the mass fraction of m-BN is 50 wt%, m-BN/PNF nanocomposite paper exhibits excellent thermal conductivity and electrical insulation. The λ ∥ and λ ⊥ are 9.68 and 0.84 W m−1 K−1, and the volume resistivity and breakdown strength are as high as 2.3 × 1015 Ω cm and 324.2 kV mm−1, respectively. The m-BN/PNF nanocomposite paper with 50 wt% m-BN also presents outstanding mechanical properties (tensile strength of 193.6 MPa) and thermal stability (thermal decomposition temperature of 640 °C).

Highlights: m-BN/PNF nanocomposite paper with nacre-mimetic layered structures prepared via sol–gel film transformation approach presents excellent thermal conductivity, incredible electrical insulation, outstanding mechanical property and thermal stability. When the mass fraction of m-BN is 50 wt%, m-BN/PNF nanocomposite paper exhibits excellent thermal conductivity and electrical insulation. The λ∥ and λ⊥ are 9.68 and 0.84 W m−1 K−1, and the volume resistivity and breakdown strength are as high as 2.3 × 1015 Ω cm and 324.2 kV mm−1, respectively. The m-BN/PNF nanocomposite paper with 50 wt% m-BN also presents outstanding mechanical properties (tensile strength of 193.6 MPa) and thermal stability (thermal decomposition temperature of 640 °C). With the rapid development of 5G information technology, thermal conductivity/dissipation problems of highly integrated electronic devices and electrical equipment are becoming prominent. In this work, "high-temperature solid-phase & diazonium salt decomposition" method is carried out to prepare benzidine-functionalized boron nitride (m-BN). Subsequently, m-BN/poly(p-phenylene benzobisoxazole) nanofiber (PNF) nanocomposite paper with nacre-mimetic layered structures is prepared via sol–gel film transformation approach. The obtained m-BN/PNF nanocomposite paper with 50 wt% m-BN presents excellent thermal conductivity, incredible electrical insulation, outstanding mechanical properties and thermal stability, due to the construction of extensive hydrogen bonds and π–π interactions between m-BN and PNF, and stable nacre-mimetic layered structures. Its λ∥ and λ⊥ are 9.68 and 0.84 W m−1 K−1, and the volume resistivity and breakdown strength are as high as 2.3 × 1015 Ω cm and 324.2 kV mm−1, respectively. Besides, it also presents extremely high tensile strength of 193.6 MPa and thermal decomposition temperature of 640 °C, showing a broad application prospect in high-end thermal management fields such as electronic devices and electrical equipment. [ABSTRACT FROM AUTHOR]

In this work, stacked SiC fibers paper‐reinforced SiC ceramic matrix composites (SiCnf/SiC CMCs) were prepared by nanoimpregnation and transient eutectic (NITE) process using ultra‐long single‐crystal SiC nanofibers. The effect of the SiCnf surface modification via boron nitride (BN) interphase deposition as well as the sintering additive (Al2O3–Y2O3) content on the density, microstructure, and mechanical properties of SiCnf/SiC CMCs has been investigated systematically. The results revealed that the laminated SiCnf/SiC CMCs feature a significant saw‐tooth‐like curve on the load–displacement test, which indicates that the obtained laminated structure with the weak interlayer binding owning to the BN coating treatment possesses significant toughening to the SiC ceramics. Specifically, the SiCnf/SiC CMCs with the sintering additive content of 12 wt% revealed a fracture toughness of over 10 MPa m1/2 after 60 min of BN interface deposition, which is 104.31% higher than that of the composites prepared without BN coating. [ABSTRACT FROM AUTHOR]

Abstract Wide‐bandgap, layered hexagonal boron nitride (h‐BN) possesses excellent electrical insulation and ultrahigh thermal conductivity simultaneously, offering a perfect candidate for the growing demands of heating dissipations in modern chip industries and power electronics. Hybrids of h‐BN with polymers fulfill the thermal management materials (TMMs) requirement of flexibility, while the composite poses severe challenges in the interfacial bonding and excess thermal resistance. To date, the practical bonding between h‐BN intrinsic surfaces and polymer matrices remains elusive. This work reports on the effective alignment of h‐BN micro‐lamellae by introducing nitrogen‐atoms‐containing polymers as inter‐lamellae bridging mediums. Based on theoretical calculations the hydrogen bonding between polymer chains and the BN surface is revealed by differential charge densities mapping. It is shown experimentally that the neuron‐like polymer bundles strongly bonding surfaces of two neighboring h‐BN platelets as direct, microscopic evidence of the structure models. An extra alignment of h‐BN induced by this strong interfacial interaction leads to a higher degree of h‐BN stacking order, boosting the thermal conduction by eight times. These results reveal one unprecedented method to non‐covalently functionalize the h‐BN surface and expand the TMMs family in the dimension of the filler size, paving the way for exploring the larger‐sized ceramic TMMs.

Surface plasmon resonance (SPR)--based biosensors compete and excel among optical biosensors because of exceptional features such as high sensitivity, label-free, and real-time measurement, allowing the observation of molecular binding kinetics. In SPR biosensors and other biosensor techniques, surface functionalization and bioreceptor attachment are effective strategies to improve sensor performance. The application of an appropriate immobilization matrix for the bioreceptor is an essential step in maximizing the absorption of the bioreceptor on the sensor surface, thereby improving a specific target-sensor interaction. Furthermore, the materials should provide excellent optical properties to enhance the response signal. The high surface-to-volume ratio and high optical absorption of 2D materials qualify these requirements, thus promising advancements for SPR biosensors. This article reviews the recent SPR biosensor study with the use of the 2D materials family to improve the sensor performance, including graphene, transition metal dichalcogenides (TMDCs), MXene, black phosphorus (BP), perovskite, and boron nitride (BN). The materials properties and enhancement mechanisms of different 2D materials are discussed comprehensively. This review was expected to provide a future perspective and design approach for 2D materials-based SPR biosensors. [ABSTRACT FROM AUTHOR]

Complementary electronics has represented the corner stone of the digital era, and silicon technology has enabled this accomplishment. At the dawn of the flexible and wearable electronics age, the seek for new materials enabling the integration of complementary metal-oxide semiconductor (CMOS) technology on flexible substrates, finds in low-dimensional materials (either 1D or 2D) extraordinary candidates. Here, we show that the main building blocks for digital electronics can be obtained by exploiting 2D materials like molybdenum disulfide, hexagonal boron nitride and 1D materials such as carbon nanotubes through the inkjet-printing technique. In particular, we show that the proposed approach enables the fabrication of logic gates and a basic sequential network on a flexible substrate such as paper, with a performance already comparable with mainstream organic technology. [ABSTRACT FROM AUTHOR]

Organic transistors are crucial components in future flexible electronics due to their excellent properties and ease of circuit integration. Previously, we demonstrated that flexible organic (polyimide) thermal transistors could be prepared using commercial graphite paper as the substrate. These materials exhibited excellent temperature sensitivity, linearity and recoverability due to the intrinsically high thermal conductivity of graphite. In this study, boron nitride (BN) sheets/polyimide hybrid dielectric layers were synthesized for the fabrication of flexible organic transistors using a commercial graphite paper. Under test, the results showed that the introduction of BN sheets was beneficial in improving the mobility and transistor characteristics of the device, as well as enhancing the overall stability. The as-fabricated transistors virtually exhibited no hysteresis at all BN contents. Boron nitride (BN) sheets were added to the fluorinated polyimide (FPI) matrix to form hybrid dielectric layer for improving the performance of flexible organic transistors fabricated on commercial graphite paper. The results showed that the device with BN/FPI hybrid dielectric layer exhibited higher output current (Id) and stability. Besides, the devices remained hysteresis-free at all tested BN sheet contents. [ABSTRACT FROM AUTHOR]

In this work, a novel thermal conductive and electrical insulation h‐BN@AgNPs/ANFs composite paper was fabricated by vacuum‐assisted filtration approach. Specifically, hexagonal boron nitride (h‐BN) was incorporated via polydopamine pretreatment and subsequent decoration by silver nanoparticles, which served as bridges to link neighboring h‐BN sheets. The results revealed that the thermal conductivity of as‐prepared composite paper increased to 1.032 W/m K with 40 wt% filler loading, about 464% higher than the pure ANFs paper, which was attributed to the efficient thermal conductive networks within the paper and strong interfacial combination through hydrogen bonding. Besides, the as‐prepared composite paper exhibited excellent mechanical property with the maximum tensile strength over 90 MPa, and good electrical insulation performance. More importantly, this work provided a promising strategy to achieve high thermal conductivity ANFs based composite paper by constructing efficient thermal conductive networks, which had potential to be used in the field of electronic packaging. [ABSTRACT FROM AUTHOR]

Negative ion mode paper spray mass spectrometry (PS-MS) suffers from intense background noise and unstable MS signal. For the first time, we reported fluorinated boron nitride nanosheet (h-FBN) assisted negative ion PS-MS for the detection of a series of molecules. We demonstrated that the introduction of h-FBN can greatly improve the detection sensitivity and signal stability in the negative ion mode. [ABSTRACT FROM AUTHOR]

[Display omitted] • Exfoliated BNNS obtained through hydrothermal reaction and in ball milling. • The rGO acts as a bridge connecting the adjacent and stacked BNNS layers, increasing the number of thermal conductivity pathways. • Highly enhanced in-plane TC up to 16.92 W m−1 k−1 with 50 wt% BNNS and 2.5 wt% rGO loading. The sharp increases in power consumption and heating capacity caused by the emergence of intelligent electronic devices necessitate the development of highly thermally conductive thermal interface materials (TIMs) with good heat dissipation properties. Boron nitride nanosheets (BNNS) are ideal materials with high thermal conductivity. Hence, it should be possible to produce flexible high thermal conductivity nanocomposites with a three-dimensional network containing ultrathin, large, and uniformly thick BNNS. In this study, large-scale (1–1.5 µm) fewer-layered (2 nm) BNNS with a high yield of 80% were prepared through the separation of a NaOH–LiCl aqueous solution by a hydrothermal method and in ball milling. Highly thermally conductive insulating nanocomposite paper with a three-dimensional bridging structure of two-component nanosheets filled with nanofibers was fabricated by a simple electrospinning–electrospraying technique. The mechanical properties of the polyimide (PI)/BNNS@reduced graphene oxide nancomposite paper were improved by 168% as compared with those of the PI/BNNS composite. With an increase in the BNNS content, a layered microstructure similar to that of natural nacre was produced, which resulted in a large in-plane thermal conductivity of 16.92 W/m·K. The described method can facilitate the design of TIMs with good electrical insulation properties, thermal stability, and flexibility. [ABSTRACT FROM AUTHOR]

Wide‐bandgap, layered hexagonal boron nitride (h‐BN) possesses excellent electrical insulation and ultrahigh thermal conductivity simultaneously, offering a perfect candidate for the growing demands of heating dissipations in modern chip industries and power electronics. Hybrids of h‐BN with polymers fulfill the thermal management materials (TMMs) requirement of flexibility, while the composite poses severe challenges in the interfacial bonding and excess thermal resistance. To date, the practical bonding between h‐BN intrinsic surfaces and polymer matrices remains elusive. This work reports on the effective alignment of h‐BN micro‐lamellae by introducing nitrogen‐atoms‐containing polymers as inter‐lamellae bridging mediums. Based on theoretical calculations the hydrogen bonding between polymer chains and the BN surface is revealed by differential charge densities mapping. It is shown experimentally that the neuron‐like polymer bundles strongly bonding surfaces of two neighboring h‐BN platelets as direct, microscopic evidence of the structure models. An extra alignment of h‐BN induced by this strong interfacial interaction leads to a higher degree of h‐BN stacking order, boosting the thermal conduction by eight times. These results reveal one unprecedented method to non‐covalently functionalize the h‐BN surface and expand the TMMs family in the dimension of the filler size, paving the way for exploring the larger‐sized ceramic TMMs. [ABSTRACT FROM AUTHOR]

The miniaturisation of electronic components requires high-performance materials with insulating and thermal conductive properties for electronic packaging and thermal management. Boron nitride nanosheets (BNNS) are a desirable thermal conductive filler due to their excellent thermal stability, chemical stability, and high thermoconductivity. However, it remains challenging to mass produce ultra-thin large-scale BNNS and combine them with small amounts of polymers to fabricate malleable thermoconductive composites for flexible electronic devices. Herein, we report a new method to prepare BNNS at high yield by high-temperature oxidation treatment followed by hydrothermal exfoliation in NaOH-LiCl solution. We further fabricated flexible, insulating, and highly thermoconductive BNNS/PI (polyimide) nanocomposite paper, via a scalable layer-by-layer process that involves electrospinning of PI fibres and eletrospraying of BNNS. The prepared BNNS have a transverse size of 1.18 µm and a thickness of 1–2.9 nm, with a high yield of 75.48% at a concentration of 3.38 mg mL− 1. The BNNS/PI nanocomposite paper exhibited an ultrahigh in-plane thermal conductivity (7.58 W m−1 K−1), 2005% higher than that of the pure PI nanofibre composite. This simple method has wide application potential in next-generation electronic devices to design thermal interface materials with excellent electrical insulation, thermostability, and flexibility. [Display omitted] • Exfoliated BNNS obtained through thermal oxidation and hydrothermal reaction. • BNNS were arranged along PI nanofibre direction by electrospraying. • Highly enhanced in-plane TC up to 7.58 W m−1 k−1 with 50 wt% BNNS loading. [ABSTRACT FROM AUTHOR]

Boron Nitride Nanotubes are valued due to their physical and chemical properties. They can be found their possible applications in the field of design and developing of optoelectronic devices of new generation. In this paper the transport and electronic properties of both clear Boron Nitride and Boron Nitride Nanotube with embedded carbon atoms have been calculated in the framework of Density Functional Theory (DFT). Results show that nanodevice with embedded carbon atoms has wider transmission spectrum than clear one. It has been computed transmission eigenvalues for both nanodevices. Nanodevice with impurity has higher transmission eigenvalues than clear one. [ABSTRACT FROM AUTHOR]

Owing to the miniaturization of power electronics and the development of portable and flexible devices, demands for highly thermally conductive, mechanically flexible, and electrically insulating composites have substantially increased. However, the conventional method to improve thermal conductivity usually yields both an undesired value (usually below 10 W m-1 K-1) and poor flexibility. Thus, a combination of all the desired properties together remains a technical challenge. Bioinspired engineering offers great promise in the synthesis and fabrication of thermal materials that are different from engineering through conventional approaches. Inspired by the interface and orientation of natural nacre, we report on thermally conductive and mechanically flexible papers based on boron nitride nanosheets (BNNSs) and graphene oxide (GO) via a simple vacuum-assisted filtration process. We experimentally show that the papers possess high thermal conductivity of 29.8 W m-1 K-1, excellent mechanical flexibility, and satisfactory electrical insulation. We attribute the high thermal conductivity to the well-designed BNNS-GO interface as well as the advantageous orientation in layered structure. This approach to constructing thermally conductive composites provides a creative opportunity for design and fabrication of high-performance materials in the near future, and this kind of paper has great potential application in next-generation commercial portable electronics. [ABSTRACT FROM AUTHOR]

Herein, a series of superhydrophobic thin polyacrylic resin-coated carbon black (CB)/hexagonal boron nitride (h-BN)@Fe 3 O 4 /cellulose composite papers with good flexibility, low density (~0.67 g/cm3), high electrical conductivity (~0.065 S/cm), good thermal conductivity (0.462 W.m−1. K−1), and with water contact angle (WCA) of 153° were successfully fabricated by a facile dip-coating/spraying method. The CB-BN@Fe 3 O 4 distribution in cellulose matrix provided high electrical conductivity in the in-plane and thickness directions. The electrical conductivity in both in-plane and thickness directions increased by increasing the number of vacuum-assisted dip-coating cycles. Moreover, these composites exhibited excellent electromagnetic interference shielding effectiveness (EMI SE) in the frequency range of 8.2–12.4 GHz. The absorption was the main mechanism for attenuation of EM waves for this composite paper. A multilayer of this composite with 12 wt% filler exhibited a higher EMI SE of 68.2 dB compared to its monolayer composite. The composites showed good thermal stability and excellent stability against washing and 150 times bending tests. Overall, this study proposes that polyacrylic resin-coated CB/BN@Fe 3 O 4 /cellulose papers can be used as wallpaper in buildings such as hospitals and antenna rooms that are exposed to electromagnetic waves. [Display omitted] • Polyacrylic resin coated CB/BN@Fe 3 O 4 /cellulose paper was prepared through a facile dip-coating/spraying method. • This composite paper showed superhydrophobic behavior with WCA of 153° and thermal conductivity of 0.462 W.m−1. K−1. • The EMI SE of this composite reaches as high as 68.2 dB in a multilayer form. • This composite was physically durable after 150 times of bending test and after washing process. • This composite can be used as portable EMI shielding materials or wallpaper in buildings such as hospitals and antenna room. [ABSTRACT FROM AUTHOR]

Carbon nanotube buckypaper has been considered as one of the promising candidates for chemiresistive sensor applications, especially with environmental monitoring purpose due to large surface area, device flexibility, and the broad spectrum of responsive chemical vapor molecules. However, one of typical drawbacks in carbon-based sensors is incomplete recovery to their initial state after chemical reactions with analytes, degrading sensing reproducibility. In this work, we present a thermally stable and robust boron nitride nanotube/carbon nanotube (BNCNT) hybrid paper for self-enhanced chemiresistive sensing with full reversibility. Boron nitride nanotube (BNNT) plays an essential role in long-term reliability (33 days) at the operating temperature of 200 °C. In addition, a finite-element method was applied to understand the thermal behavior of the BNCNT network structure. The BNCNT paper-based chemiresisitve sensor exhibited highly sensitive, selective, and fully reversible responses to NO 2 without external heating. Also, the sensor demonstrated the detection limit of parts per billion (ppb)-levels under strain with high reliability. With these remarkable strengths, significantly facile and cost-effective fabrication processes provide an environmental sensing platform for use in smart clothing with wearable electronics. • Boron nitride nanotube/carbon nanotube (BNCNT)-based chemiresistive sensor with full reversibility was developed. • The BNCNT paper exhibits a highly sensitive detection to NO 2 at room temperature. • The detection limit (DL) is 3.41 parts per billion (ppb) even under strained conditions with high reliability. • The BNCNT papers maintained its self-enhanced temperature of 200 °C during a long-term stability test for 33 days. • The BNNT plays a major role in the long-term reliability of maintaining a temperature of CNT networks. [ABSTRACT FROM AUTHOR]

The document is a contents list for the journal CrystEngComm. It highlights the articles and papers featured in the current issue, including topics such as cobalt coordination polymers, environmental science, polymorphism, and lithium storage. The journal aims to advance the understanding and design of solid-state and crystalline materials. The Royal Society of Chemistry, a leading chemistry community, publishes the journal and reinvests its profits back into the chemistry community. [Extracted from the article]

[Display omitted] • A composite paper was prepared by combining aramid nanofibers, boron nitride nanotubes, and polyethyleneimine. • Elaborating interfacial hydrogen bonds design can optimize the mechanical properties of composite paper. • The composite paper has high thermal conductivity and unique dielectric performance. Aramid paper is ubiquitous in advanced electronics and high-voltage equipment by virtue of their outstanding dielectric properties, mechanical reliability, and thermal stability. However, their limited thermal conductivity still fails to satisfy the stringent demands for heat dissipation in applications with high power and high energy density. Herein, we report a highly thermally conductive composite paper prepared by synergistically combining one-dimensional (1D) aramid nanofibers (ANFs), 1D edge-hydroxylated boron nitride nanotubes (BNNTs), and polyethyleneimine (PEI). The resultant composite paper exhibits high thermal conductivity (9.91 Wm−1K−1), low dielectric loss (<0.01), and ultrahigh electrical breakdown strength (∼334 kV/mm) with an exceptional heat resistance performance. Three-dimensional hydrogen bonding networks were constructed between the ANF framework, PEI, and BNNTs, endowing the composite paper with a superior tensile strength (up to 317 MPa) and Young's modulus (∼7.7 GPa), which are significantly higher than those of the commercial Nomex T410 paper. This research provides important insights into the design and fabrication of multifunctional insulating paper for application in modern integrated electronic and power systems. [ABSTRACT FROM AUTHOR]

Owing to the rapid development of high-power and minimized electronic devices, the materials with ultra-flexibility and effective heat dissipation have attracted much interest. Herein, the high thermally conductive epoxidized natural rubber (ENR) papers with layered structures based on boron nitride (BN) platelets are reported. First, polyrhodanine (PRd) was coated on the surface of BN platelets via oxidative polymerization of rhodanine (Rhd), which was initiated by the absorbed (S 2 O 8)2- ions. Then, BN-PRd platelets were grafted with ENR chains using a mechanochemical method due to the presence of N–C S groups in PRd, allowing the combination of PRd and ENR chains with stable covalent bonds. Moreover, the grafted ENR chains acted as bridges between adjacent BN platelets and improved the heat transfer ability of BN-PRd/ENR thermally conductive composite papers. The as-prepared ultra-flexible 30 wt% BN-PRd/ENR thermally conductive composite papers rendered high in-plane (λ ∥) and through-plane (λ ⊥) thermal conductivity of 14.57 and 0.52 W/(mK), respectively, which were correspondingly 8094% and 289% of pure ENR paper (0.18 W/(mK)). Also, Young's modulus of the 30 wt% BN-PRd/ENR thermally conductive composite paper was 25.90 MPa. Overall, the as-fabricated BN-PRd/ENR thermally conductive composite papers demonstrated high flexibility, excellent mechanical robustness, outstanding thermal conductivity, and superior electronic illustration, indicating potential applications in areas of electronic components as thermal interface materials. [Display omitted] [ABSTRACT FROM AUTHOR]

High-voltage direct-current (HVDC) dry bushing capacitor-core insulation is composed of epoxy resin-impregnated insulating paper (RIP). To improve the thermal conductivity, breakdown strength, and space charge characteristics of RIP, 0.1 wt % nano-cellulose fiber (CNF)-modified RIP (CNF/RIP), 2.5–30 wt % hexagonal boron nitride (h-BN)-modified RIP (h-BN/RIP), and 2.5–30 wt % h-BN + 0.1 wt % CNF-modified RIP (h-BN + 0.1 wt % CNF/RIP) were prepared. Scanning electron microscopy (SEM) was implemented; the thermal conductivity, DC conductivity, DC breakdown strength, and space charge characteristics were tested. The maximum thermal conductivity of h-BN + 0.1 wt % CNF/RIP was 0.376 W/m.K with a h-BN content of 30 wt %. The thermal conductivity was 85.2% higher than that of unmodified RIP. The breakdown strength and charge suppression were the best in the case of 10 wt % h-BN + 0.1 wt % CNF/RIP. The maximum breakdown strength was 11.2% higher than that of unmodified RIP. These results can play a significant role in the research and development of insulation materials for HVDC dry bushing. [ABSTRACT FROM AUTHOR]