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HighlightsCellulose aerogels were prepared by hydrogen bonding driven self-assembly, gelation and freeze-drying.The skin-core structure of CCA@rGO aerogels can form a perfect three-dimensional bilayer conductive network.Outstanding EMI SE (51 dB) is achieved with 3.05 wt% CCA@rGO, which is 3.9 times higher than that of the co-blended composites.In order to ensure the operational reliability and information security of sophisticated electronic components and to protect human health, efficient electromagnetic interference (EMI) shielding materials are required to attenuate electromagnetic wave energy. In this work, the cellulose solution is obtained by dissolving cotton through hydrogen bond driving self-assembly using sodium hydroxide (NaOH)/urea solution, and cellulose aerogels (CA) are prepared by gelation and freeze-drying. Then, the cellulose carbon aerogel@reduced graphene oxide aerogels (CCA@rGO) are prepared by vacuum impregnation, freeze-drying followed by thermal annealing, and finally, the CCA@rGO/polydimethylsiloxane (PDMS) EMI shielding composites are prepared by backfilling with PDMS. Owing to skin-core structure of CCA@rGO, the complete three-dimensional (3D) double-layer conductive network can be successfully constructed. When the loading of CCA@rGO is 3.05 wt%, CCA@rGO/PDMS EMI shielding composites have an excellent EMI shielding effectiveness (EMI SE) of 51 dB, which is 3.9 times higher than that of the co-blended CCA/rGO/PDMS EMI shielding composites (13 dB) with the same loading of fillers. At this time, the CCA@rGO/PDMS EMI shielding composites have excellent thermal stability (THRI of 178.3 °C) and good thermal conductivity coefficient (λ of 0.65 W m-1 K-1). Excellent comprehensive performance makes CCA@rGO/PDMS EMI shielding composites great prospect for applications in lightweight, flexible EMI shielding composites.Graphic abstract

HighlightsHierarchically multifunctional polyimide composite films were fabricated by hierarchical design and assembly strategy.Polyimide composite films have three functional layers and integrates high thermal conductivity (95.40 W (m K)−1), excellent EMI shielding (34.0 dB) and good tensile strength (93.6 MPa).Polyimide composite films present broad application prospects in electronics fields according to the test results in the central processing unit.The development of lightweight and integration for electronics requires flexible films with high thermal conductivity and electromagnetic interference (EMI) shielding to overcome heat accumulation and electromagnetic radiation pollution. Herein, the hierarchical design and assembly strategy was adopted to fabricate hierarchically multifunctional polyimide composite films, with graphene oxide/expanded graphite (GO/EG) as the top thermally conductive and EMI shielding layer, Fe3O4/polyimide (Fe3O4/PI) as the middle EMI shielding enhancement layer and electrospun PI fibers as the substrate layer for mechanical improvement. PI composite films with 61.0 wt% of GO/EG and 23.8 wt% of Fe3O4/PI exhibits high in-plane thermal conductivity coefficient (95.40 W (m K)−1), excellent EMI shielding effectiveness (34.0 dB), good tensile strength (93.6 MPa) and fast electric-heating response (5 s). The test in the central processing unit verifies PI composite films present broad application prospects in electronics fields.

Transition metal carbides/nitrides/carbonitrides (MXenes) exhibit tremendous potential for optical applications due to their diverse elemental composition and adaptable structural properties. Based on introducing the preparation methods and optical properties of MXenes, this review focuses on the latest advances in MXenes‐based optical functional materials, and analyzes the performance enhancement mechanisms of MXenes‐based optical functional materials for photothermal conversion and photocatalysis. The key scientific and technical bottlenecks in the field of MXenes‐based optical functional materials are pointed out, and the future development trends and research directions of MXenes‐based optical functional materials are prospected. This review focuses on the latest advances of MXenes‐based optical functional materials, and analyzes the performance enhancement mechanisms of MXenes‐based optical functional materials for photothermal conversion and photocatalysis. MXenes‐based photothermal conversion materials can be specifically applied to desalination, wearable devices, and photothermal therapy, and MXenes‐based photocatalysis materials can be specifically applied to water treatment, H2 production, and CO2 reduction.

The potential of three‐dimensional (3D) printing technology in the fabrication of advanced polymer composites is becoming increasingly evident. This review discusses the latest research developments and applications of 3D printing in polymer composites. First, it focuses on the optimization of 3D printing technology, that is, by upgrading the equipment or components or adjusting the printing parameters, to make them more adaptable to the processing characteristics of polymer composites and to improve the comprehensive performance of the products. Second, it focuses on the 3D printable novel consumables for polymer composites, which mainly include the new printing filaments, printing inks, photosensitive resins, and printing powders, introducing the unique properties of the new consumables and different ways to apply them to 3D printing. Finally, the applications of 3D printing technology in the preparation of functional polymer composites (such as thermal conductivity, electromagnetic interference shielding, biomedicine, self‐healing, and environmental responsiveness) are explored, with a focus on the distribution of the functional fillers and the influence of the topological shapes on the properties and functional characteristics of the 3D printed products. The aim of this review is to deepen the understanding of the convergence between 3D printing technology and polymer composites and to anticipate future trends and applications. This review explores the promising intersection of three‐dimensional printing technology and advanced polymer composites, highlighting recent advancements in optimizing printing processes, developing innovative materials, and applying these to create functional products with enhanced properties such as thermal conductivity, biocompatibility, and so on.

In this work, carbon nanotubes pillared grew on exfoliated graphite by the microwave-assisted method is utilized as thermally conductive fillers (CPEG) in polyimide (PI) to fabricate CPEG/PI thermally conductive composites with the combining ways of “in-situ polymerization, electrospinning, lay-up, and hot-pressing”. The prepared CPEG/PI composites realized the maximum thermal conductivity ( λ , 1.92 W m −1 K −1 ) at low CPEG amount (10 wt%), much higher than that of pure PI (0.28 W m −1 K −1 ). The λ of CPEG/PI composites show almost no change after 1000 cycles of heating and cooling at the temperature of 25−100 °C. The finite element analysis simulates the nano-/microscale heat transfer in CPEG/PI composites to reveal the internal reason of the λ enhancement. The improved thermal conductivity model and empirical equation could better reflect the actual λ change trend of CPEG/PI composites. The actual application test shows the CPEG/PI composites could significantly reduce the operating temperature of the CPU in mobile phone.

Chronology of debris flow deposits (DFD) is crucially important in understanding fan evolution and assessing the risks of future extreme disaster events. To establish the debris flow history in a long-term temporal framework, multiple debris flow and flash flood events were examined from the Sandaoqiao (SDQ) gully near the large-scale active Xianshuihe faults, eastern Tibetan Plateau. The rough and discontinuous structures indicate DFD are characterized by “linear stone structure” and boulders enclosed by clayey silts in the SDQ gully. On the basis of debris flow sedimentary characteristics, we develop a valid sampling strategy involving 14 C and OSL dating methods (13 radiocarbon and 3 OSL ages) on the debris flow fan. The major stages of debris flow aggradation were identified at ~ 35 kyr B.P., 23‒22 kyr B.P., ~ 13 kyr B.P. and 3.9‒1.4 kyr B.P. since the Last Glacial (last ~ 35 kyr B.P.). And gully-fill deposits were more abundant during the latest Pleistocene (35‒13 ka) than current phase. Late Holocene debris flow and flash flood events recur in the mid-channel from 3.9‒3.8 to 1.9‒1.4 kyr B.P., which was probably triggered by palaeo-earthquake events associated with active faults. The current phase is dominated by debris flood events and the maximum discharge is estimated as ~ 290 m 3 /s. This study provides key chronology for understanding multiple debris flow stages associated with regional tectonic activity and climatic change in the eastern Tibetan Plateau.

The developing flexible electronic equipment are greatly affected by the rapid accumulation of heat, which is urgent to be solved by thermally conductive polymer composite films. However, the interfacial thermal resistance (ITR) and the phonon scattering at the interfaces are the main bottlenecks limiting the rapid and efficient improvement of thermal conductivity coefficients (λ) of the polymer composite films. Moreover, few researches were focused on characterizing ITR and phonon scattering in thermally conductive polymer composite films. In this paper, graphene oxide (GO) was aminated (NH2-GO) and reduced (NH2-rGO), then NH2-rGO/polyimide (NH2-rGO/PI) thermally conductive composite films were fabricated. Raman spectroscopy was utilized to innovatively characterize phonon scattering and ITR at the interfaces in NH2-rGO/PI thermally conductive composite films, revealing the interfacial thermal conduction mechanism, proving that the amination optimized the interfaces between NH2-rGO and PI, reduced phonon scattering and ITR, and ultimately improved the interfacial thermal conduction. The in-plane λ (λ||) and through-plane λ (λ⊥) of 15 wt% NH2-rGO/PI thermally conductive composite films at room temperature were, respectively, 7.13 W/mK and 0.74 W/mK, 8.2 times λ|| (0.87 W/mK) and 3.5 times λ⊥ (0.21 W/mK) of pure PI film, also significantly higher than λ|| (5.50 W/mK) and λ⊥ (0.62 W/mK) of 15 wt% rGO/PI thermally conductive composite films. Calculation based on the effective medium theory model proved that ITR was reduced via the amination of rGO. Infrared thermal imaging and finite element simulation showed that NH2-rGO/PI thermally conductive composite films obtained excellent heat dissipation and efficient thermal management capabilities on the light-emitting diodes bulbs, 5G high-power chips, and other electronic equipment, which are easy to generate heat severely.

Highlights By simultaneously incorporating the magnetic filler-modified boron nitride nanosheets (M@BNNS) and the non-magnetic filler U-BNNS into the polymer matrix, a three-dimensional heat conduction pathway composites are obtained under a horizontal magnetic field. Owing to the microstructural design of the 3D-bridging architecture, with the addition of only 5 wt% U-BNNS, the λ ⊥ of composites achieved 2.88 W m −1  K −1 , representing a remarkable increase of 194.2% compared to single-oriented composites. The 3D-bridging architecture composite also demonstrates excellent flame retardancy, attributed to the synergistic mechanisms of condensed and gas phases, effectively mitigating the risks of thermal runaway in electronic devices. The microstructure design for thermal conduction pathways in polymeric electrical encapsulation materials is essential to meet the stringent requirements for efficient thermal management and thermal runaway safety in modern electronic devices. Hence, a composite with three-dimensional network (Ho/U-BNNS/WPU) is developed by simultaneously incorporating magnetically modified boron nitride nanosheets (M@BNNS) and non-magnetic organo-grafted BNNS (U-BNNS) into waterborne polyurethane (WPU) to synchronous molding under a horizontal magnetic field. The results indicate that the continuous in-plane pathways formed by M@BNNS aligned along the magnetic field direction, combined with the bridging structure established by U-BNNS, enable Ho/U-BNNS/WPU to exhibit exceptional in-plane ( λ // ) and through-plane thermal conductivities ( λ ⊥ ). In particular, with the addition of 30 wt% M@BNNS and 5 wt% U-BNNS, the λ // and λ ⊥ of composites reach 11.47 and 2.88 W m −1  K −1 , respectively, which representing a 194.2% improvement in λ ⊥ compared to the composites with a single orientation of M@BNNS. Meanwhile, Ho/U-BNNS/WPU exhibits distinguished thermal management capabilities as thermal interface materials for LED and chips. The composites also demonstrate excellent flame retardancy, with a peak heat release and total heat release reduced by 58.9% and 36.9%, respectively, compared to WPU. Thus, this work offers new insights into the thermally conductive structural design and efficient flame-retardant systems of polymer composites, presenting broad application potential in electronic packaging fields.

Highlights Copolymer of divinylphenyl-acryloyl chloride copolymers (PDVB- co -PACl) is designed and synthesized to graft on the surface of aluminum nitride (AlN) to improve its hydrolysis resistance. AlN fillers functionalized by PDVB- co -PACl with the molecular weight of 5100 g mol -1 exhibits the highest hydrolysis resistance and the lowest interfacial thermal resistance. When the mass fraction of AlN@PDVB- co -PACl is 75 wt% and the grafting density of PDVB- co -PACl is 0.8 wt%, the λ for AlN@PDVB- co -PACl/PMHS composites is 1.14 W m -1  K -1 and maintains 99.1% after soaking in 90 °C deionized water for 80 h. A series of divinylphenyl-acryloyl chloride copolymers (PDVB- co -PACl) is synthesized via atom transfer radical polymerization employing tert-butyl acrylate and divinylbenzene as monomers. PDVB- co -PACl is utilized to graft on the surface of spherical aluminum nitride (AlN) to prepare functionalized AlN (AlN@PDVB- co -PACl). Polymethylhydrosiloxane (PMHS) is then used as the matrix to prepare thermally conductive AlN@PDVB- co -PACl/PMHS composites with AlN@PDVB- co -PACl as fillers through blending and curing. The grafting of PDVB- co -PACl synchronously enhances the hydrolysis resistance of AlN and its interfacial compatibility with PMHS matrix. When the molecular weight of PDVB- co -PACl is 5100 g mol −1 and the grafting density is 0.8 wt%, the composites containing 75 wt% of AlN@PDVB- co -PACl exhibit the optimal comprehensive performance. The thermal conductivity ( λ ) of the composite is 1.14 W m −1  K −1 , which enhances by 20% and 420% compared to the λ of simply physically blended AlN/PMHS composite and pure PMHS, respectively. Meanwhile, AlN@PDVB- co -PACl/PMHS composites display remarkable hydrothermal aging resistance by retaining 99.1% of its λ after soaking in 90 °C deionized water for 80 h, whereas the λ of the blended AlN/PMHS composites decreases sharply to 93.7%.

The Circulatory System Based Optimisation (CSBO) stands as a nascent metaheuristic optimisation algorithm known for its proficiency in tackling global optimisation problems. The authors introduce the Multi‐strategy Enhanced CSBO (MECSBO), an algorithm designed for global optimisation and Reliability‐based Design Optimisation (RBDO). MECSBO integrates adaptive inertia weight, golden sine operator and chaos strategy to augment the convergence capacity and efficiency of the original CSBO. Furthermore, MECSBO‐based RBDO algorithm is presented to address RBDO problem. The comparative analysis utilising standard real‐world benchmark functions has been carried out to validate the effectiveness of the proposed MECSBO. Several RBDO problems, including three typical numerical examples and three engineering cases, are used to show abilities of the proposed MECSBO‐based RBDO algorithm. The results demonstrated that MECSBO is outperformed comparing to the state‐of‐the‐art algorithms in terms of accuracy, efficiency, and robustness in RBDO problems. The authors introduce the Multi‐strategy Enhanced Circulatory System Based Optimisation (MECSBO), an algorithm designed for global optimisation and Reliability‐based Design Optimisation (RBDO). MECSBO integrates adaptive inertia weight, golden sine operator and chaos strategy to augment the convergence capacity and efficiency of the original CSBO. Furthermore, MECSBO‐based RBDO algorithm is presented to address RBDO problem.