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Thermal conductive polymer composite prepared by 3D printing technology, which has a highly vertically oriented carbon fiber structure.

Considering the significant threat of heat to electronic equipment and the heat dissipation problems existing in powerful systems, thermal management materials are in high demand. In conjunction with the increasing desire of dissipating heat and stabilizing temperature, high thermal conductivity and phase change latent heat are attracting more attention when designing thermal management material. This work proposes a strategy to combine phase change matrix and thermally conductive filler using freeze casting. The highest thermal conductivity reaches 23.1 W m-1 K-1 accompanied by 62 J g-1 phase change latent heat. Meanwhile, replacing ice with organic phase change material in freeze casting can result in an aligned structure. This discovery will pave a novel way for introducing thermal latent heat without abandoning the aligned structure.

Simultaneous achievement of high thermal transportation performance and superior mechanical properties in a same thermal management composite film.

Correction for ‘Ultrahigh thermal conductive polymer composites by the 3D printing induced vertical alignment of carbon fiber’ by Zhenbang Zhang et al., J. Mater. Chem. A, 2023, https://doi.org/10.1039/D3TA01676E.

Two-dimensional nanomaterials is an intensive research area, but the anisotropy of two-dimensional nanomaterials limits its performance release and application. As a typical two-dimensional nanomat...

In this paper, the fracture surfaces of a light-conversion film were observed using a scanning electron microscope (SEM), and then, the fluorescence spectra and mechanical properties of the film were tested. The SEM results show that the average diameter of the light conversion agent is 500 nm. The results of the mechanical properties tests show that the tensile strengths of light-conversion film increase from 9.86 to 12.16 MPa and that the strain at breakage increases from 2.37% to 2.75%. In addition, the application effects of the light-conversion film were studied. The results indicate that plant height, length of the maximum leaf, width of the maximum leaf and breadth of the plants increase by 24.43%, 15.30%, 15.60% and 19.07%, respectively. The quality of Chinese flowering cabbages treated with the light-conversion film is superior, including a 9.09% increase in the soluble protein content, a 21.27% increase in the polyphenol content, and a 19.15% increase in the soluble sugar content. Based on these results, light-conversion films can be applied in agricultural production.

Graphene is a new type of carbon material with a flexible, two-dimensional structure. Due to the excellent stability of its lattice structure and its mechanical flexibility, graphene-based materials can be applied in flexible humidity sensors. At present, the application of graphene-based flexible humidity sensors in the fields of medical care and environmental monitoring is attracting widespread attention. In this review, the basic properties of graphene oxide (GO) and reduced graphene oxide (rGO) as moisture-sensitive materials and methods for their preparation were introduced. Moreover, three methods for improving the performance of moisture-sensitive materials were discussed. The working principle of different types of graphene-based humidity sensors were introduced. The progress in the research on graphene-based flexible humidity sensors in four respects: Human respiration, skin moisture, human sweat, and environmental humidity were discussed. Finally, the future research, following the development trends and challenges, to develop the potential of integrated, graphene-based flexible humidity sensors were discussed.

Pine wilt disease (PWD) caused by pine wood nematode (PWN, Bursaphelenchus xylophilus) originated in North America and has since spread to Asia and Europe. PWN is currently a quarantine object in 52 countries. In recent years, pine wilt disease has caused considerable economic losses to the pine forest production industry in China, as it is difficult to control. Thus, one of the key strategies for controlling pine wilt disease is to identify epidemic points as early as possible. The use of hyperspectral cameras mounted on drones is expected to enable PWD monitoring over large areas of forest, and hyperspectral images can reflect different stages of PWD. The trend of applying hyperspectral techniques to the monitoring of pine wilt disease is analyzed, and the corresponding strategies to address the existing technical problems are proposed, such as data collection of early warning stages, needs of using unmanned aerial vehicles (UAVs), and establishment of models after preprocessing.

Thermal interface materials (TIM) have become a leading solution to achieve lower operating temperature in electronic devices. To improve thermal conductivity and to simultaneously reduce thermal resistance, this work investigates the thermal properties for interface materials with carbon fiber and graphite. When the ratio between carbon fiber to graphite is 1:1, the thermal resistance can be reduced to 1.8 × 10−4 K m2 W−1 at 30 psi, although the bulk thermal conductivity is lowered from 34 to 19 W m−1 K−1. The synergistic effect between carbon fiber and graphite is investigated. Surface roughness of TIMs was measured and two different types of thermal conductivity measurement were applied to demonstrate that graphite makes a contribution to bulk thermal conductivity where a CF played an important role for smoothing the surface, thereby lowering the thermal resistance. In real applications, the hybrid filler is shown to perform better in enhancing the heat conduction for electrical packaging.

Defective BiOBr nanosheets with ultrathin thickness and surface-confined pits have been synthesized through a dual control of cetyltrimethylammonium bromide (CTAB) and polyvinyl pyrrolidone (PVP). The photocatalytic activity of the obtained defective BiOBr nanosheets was evaluated for the removal of rhodamine B (RhB), ciprofloxacin (CIP) and oxygen evolution from water. The as-prepared defective BiOBr nanosheets displayed significantly increased activity for pollutant degradation and oxygen evolution. The enhanced photocatalytic activity was ascribed to the improved light harvesting, suppression of charge recombination, and an increase in the number of active sites for photocatalytic reaction. The electronic structure of the defective BiOBr ultrathin nanosheets with confined pits has been tuned and thus varied the photocatalytic mechanism for pollutant degradation. The active species have changed from hole for BiOBr nanoplates to superoxide radical (O2.−) and hole for defective BiOBr nanosheets determined by ESR analysis and trapping experiments.

A facile one-step solvothermal route for the preparation of high-efficient red fluorescence carbon dots (RCDs) is developed using 2-aminophenol as carbon source. The as-prepared RCDs indicate excitation-independent emission at 615 nm, high absolute photoluminescence (PL) quantum yield (24%) in ethanol, excellent water solubility, high optical stability and sensitive pH response behavior. The RCDs-based “off-on” reversible probe can be used to detect H+ and OH−. The quenching and recovering effects can be obviously observed by naked eyes due to the combination effect between the target ions and the surface functional groups of RCDs, resulting in breaking or recombination of the quenchers. Moreover, a remarkable fluorescence enhancement behavior with the increase of pH from 4 to 13 can be induced by the RCDs, which can be also used to detect H+ and OH− in urine of cattle and lake water, exhibiting a promising platform of the RCDs for environmental and biological sensing applications.