In Situ Transition of Amorphous Carbon to Graphite-like Structures Using MXene as a Template for Fast and Long-Lasting Macrosuperlubricity.

Achieving fast and long-lasting superlubricity in two-dimensional (2D) materials under high-stress conditions is challenging due to their susceptibility to structural deformations, limited load-bearing capacity, oxidation, and thermal degradation. This study introduces an innovative strategy by utilizing a composite of MXene and H-DLC, where, under high-stress conditions, H-DLC acts as a preferential energy-absorbing phase. MXene serves as a template to rapidly and continuously transform the absorbed energy into graphene-like structures, forming an in situ heterogeneous MXene/graphene-like interface.

Friction Behavior and Structural Evolution of Hexagonal Boron Nitride: A Relation to Environmental Molecules Containing -OH Functional Group.

Sliding contact experiments and first-principles calculations were performed to elucidate the roles of environmental molecules containing -OH functional groups on the friction behavior and structural evolution of hexagonal boron nitride (-BN). A significant decrease in the friction coefficient (COF) is established by the physisorption and dissociative adsorption of molecules containing -OH functional groups on -BN, compared with that in a H or N atmosphere. A key finding is the existence of two friction mechanisms to reconstruct the sliding interface for -BN crystallites in humid air and carbon contaminant (CHOH and CHOH) atmospheres, which is verified by the friction behavior and morphologies of the wear track.

High Loading Capacity and Wear Resistance of Graphene Oxide/Organic Molecule Assembled Multilayer Film.

Taking advantage of the strong charge interactions between negatively charged graphene oxide (GO) sheets and positively charged poly(diallyldimethylammonium chloride) (PDDA), self-assembled multilayer films of (GO/PDDA) were created on hydroxylated silicon substrates by alternating electrostatic adsorption of GO and PDDA. The formation and structure of the films were analyzed by means of water contact angle measurement, thickness measurement, atomic force microscopy (AFM) and X-ray photoelectron spectroscopy (XPS). Meanwhile, tribological behaviors in micro- and macro- scale were investigated by AFM and a ball-on-plate tribometer, respectively.

Quasi-isotropically thermoconductive, antiwear and insulating hierarchically assembled hexagonal boron nitride nanosheet/epoxy composites for efficient microelectronic cooling.

Herein, Pebax functionalized h-BNNSs (P-BNNSs) fabricated by a mechanical exfoliation and in-situ modification process are employed to improve the thermal conductivity and antiwear performance of epoxy resin (EP). Pebax can effectively improve the dispersibility of P-BNNSs, achieving hierarchical assembly of P-BNNSs in EP matrix during EP curing process to form a multinetwork structure only at a low P-BNNS filling contents (≤6 wt%). This multinetwork structure can act as excellent heat conductive pathways to realize simultaneously vertical and horizontal heat diffusion, obtaining quasi-isotropical thermal conductive P-BNNS/EP composites.

Quasi-Isotropically Thermal Conductive, Highly Transparent, Insulating and Super-Flexible Polymer Films Achieved by Cross Linked 2D Hexagonal Boron Nitride Nanosheets.

Polymer-based thermal management materials (TIMs) show great potentials as TIMs due to their excellent properties, such as high insulation, easy processing, and good flexibility. However, the limited thermal conductivity seriously hinders their practical applications in high heat generation devices. Herein, highly transparent, insulating, and super-flexible cellulose reinforced polyvinyl alcohol/nylon12 modified hexagonal boron nitride nanosheet (PVA/(CNC/PA-BNNS)) films with quasi-isotropic thermal conductivity are successfully fabricated through a vacuum filtration and subsequent self-assembly process.

Boron Nitride Nanosheet Dispersion at High Concentrations.

There is an increasing demand for boron nitride nanosheets (BNNSs) for a range of applications such as advanced composite materials, ion/gas selective membranes, and energy storage. These applications require stable, high-concentration BNNS dispersions as a precursor, which is a challenge because BNNSs do not disperse easily. We report a simple, yet efficient, mechanochemical exfoliation technique to prepare functionalized BNNSs with excellent dispersibility in water and organic solvents.

Three-dimensional network-like structure formed by silicon coated carbon nanotubes for enhanced microwave absorption.

The rapid development of electronic technology generates a great deal of electromagnetic wave (EMW) that is tremendously hazardous to environment and human health. Correspondingly, the high efficient EMW absorption materials with lightweight, high capacity and broad bandwidth are highly required. Herein, a series of three-dimensional (3D) network-like structure formed by silicon coated carbon nanotubes (NW-CNT@SiO) are massively prepared through an improved sol-gel process.

Facile fabrication of Hildewintera-colademonis-like hexagonal boron nitride/carbon nanotube composite having light weight and enhanced microwave absorption.

Hildewintera-colademononis-like hexagonal boron nitride carbon nanotubes (BN@CNT) composites can be fabricated via two steps: a composite structure predesign in a solvent and a subsequent thermal treatment process at high temperature. The as-obtained hildewintera-colademononis-like BN@CNT composites contain porous h-BN microrods as stems and CNTs as spines. The densities and specific surface area of these BN@CNT composites can be tuned by adjusting the relative amounts of CNTs in the composites, which can reach 0.

Facile fabrication of carbon microspheres decorated with B(OH) and α-FeO nanoparticles: Superior microwave absorption.

We demonstrate that novel three-dimensional (3D) B(OH) and α-FeO nanoparticles decorated carbon microspheres (B(OH)/α-FeO-CMSs) can be fabricated via a facile thermal treatment process. The carbon microspheres with diameter of 1-3μm and decorated B(OH) and α-FeO nanoparticles with diameters of several to tens of nanometers are successfully fabricated. These novel 3D B(OH)/α-FeO-CMS composites exhibit enhanced microwave absorption with tunable strong absorption wavebands in the frequency range of 2-18GHz.

Selective separation of oil and water with mesh membranes by capillarity.

The separation of oil and water from wastewater generated in the oil-production industries, as well as in frequent oil spillage events, is important in mitigating severe environmental and ecological damage. Additionally, a wide arrange of industrial processes require oils or fats to be removed from aqueous systems. The immiscibility of oil and water allows for the wettability of solid surfaces to be engineered to achieve the separation of oil and water through capillarity.

Boron nitride nanosheets as improved and reusable substrates for gold nanoparticles enabled surface enhanced Raman spectroscopy.

Atomically thin boron nitride (BN) nanosheets have been found to be excellent substrates for noble metal particles enabled surface enhanced Raman spectroscopy (SERS), thanks to their good adsorption of aromatic molecules, high thermal stability and weak Raman scattering. Faceted gold (Au) nanoparticles have been synthesized on BN nanosheets using a simple but controllable and reproducible sputtering and annealing method. The size and density of the Au particles can be controlled by sputtering time, current and annealing temperature etc.