Flame-retardant coatings are crucial for safety. However, flame-retardant materials are often hydrophilic, causing them to easily dissolve in high-humidity environments, thereby significantly limiting their durability. Thus, the integration of water repellency and flame retardancy into a single coating is ideal for developing durable and flame-retardant materials. In this study, a robust skin-inspired double-layer coating was fabricated by using spray coating. An intumescent flameretardant "dermis" layer, comprising ammonium polyphosphate (APP), polydopamine (PDA), and 1-[3-(trimethoxysilyl) propyl]urea (UPTMS), provides the primary heat insulation and flame retardancy functions. A superhydrophobic "epidermis" layer, constructed using silicone nanofilaments (Si NFs), poly(vinylidene fluoride-co-hexafluoropropylene) (PVDF-HFP), and triethoxy-1H,1H,2H,2H-heptadecafluorodecylsilane (PFDTS), protects flame-retardant materials in moist conditions. Owing to its intumescent effect, the obtained coating demonstrated excellent flame retardancy, with the fire self-extinguishing immediately after the removal of flame source. It achieves a limiting oxygen index (LOI) of 85.3% and significantly decreases the peak heat release rate (PHRR) and the fire growth index (FGI) of 59.20 kW & centerdot;m-2 and 0.789 kW & centerdot;m-2 & centerdot;s-1, respectively. The epidermal layer demonstrated outstanding superhydrophobicity and remarkable mechanical stability, with the water contact angle remaining above 160 degrees after 1000 bending cycles between 90 degrees and 180 degrees. Together with the facile spray-coating process, the biomimetic design of this intumescent flame-retardant and superhydrophobic coating provides a feasible and sustainable strategy for constructing durable fireproofing materials.

Electrically controlled solid propellants (ECSPs) are promising candidates for electrically driven energy conversion systems where electrical conduction, Joule heating, phase transition, and combustion processes are strongly coupled. However, the transient evolution of the solid–liquid phase transition and its interaction with electrical energy deposition remain insufficiently understood due to the lack of effective in situ diagnostic approaches. In this study, a laser-based optical diagnostic method combined with synchronized electrical measurements was developed to visualize and quantitatively characterize the transient phase transition and combustion surface evolution of ECSPs under electrical excitation. A controlled end-face energy-release configuration was established to regulate the electrical conduction pathway and achieve localized energy deposition. The proposed optical diagnostic method enables real-time observation of molten-phase formation, liquid-phase interconnection, and surface regression behaviors during the energy-release process. The results reveal that electrical activation initially induces the formation and expansion of a molten layer on the propellant surface, followed by rapid energy release triggered by the establishment of a continuous conductive pathway. Contact pressure significantly influences the phase transition and energy-release characteristics by modifying the interfacial contact conditions and electrical transport behavior. Furthermore, the surface regression process exhibits a strong correlation with the electrical response, demonstrating the coupling between energy deposition and material regression. This study provides an effective optical diagnostic approach for investigating transient phase transitions and electrothermal coupling behaviors in ECSPs, offering valuable insights into the design and control of electrically activated energy conversion systems.

To tackle UAV on-board electronics' key pain points-single functionality, excessive weight, and poor thermalelectromagnetic integration-a sustainable multifunctional composite phase change aerogel (C-PCA) was developed via a dual biomass synergy: waste paper (WP) builds a macro load-bearing framework, while spent coffee grounds (SCG)-derived cellulose nanofibers (CNF) enable nanoscale cross-linking to jointly enhance structural stability. The fabrication involves three concise steps: directional freezing-freeze-drying to form CNF/ WP aerogel, carbonization (700 degrees C, N2 atmosphere) to obtain a porous carbonized aerogel (C-aerogel), and vacuum impregnation of PEG-1000 to prepare C-PCA. The optimal C-aerogel (Sample S1, WP/CNF mass ratio = 8:2) withstands a 200 g load without deformation; C-PCA retains a melting enthalpy of 130.2 J g-1 (91.8% of pure PEG-1000), reduces supercooling by 1.4 degrees C, and shows no leakage after heating at 60 degrees C for 120 min. Its thermal conductivity (351.4 mW m-1 K-1, 1.5 times that of pure PEG-1000) ensures efficient heat transfer, while it reaches the phase transition temperature in 121 s under 1600 mW cm-2 simulated solar irradiation and 85 degrees C in 540 s under 15 V (UAV-adapted voltage). In the X-band (8.2-12.4 GHz), C-PCA achieves 33.98 dB electromagnetic interference (EMI) shielding (absorption-dominated, meeting UAV standards) and excellent infrared camouflage (surface temperature 23.1 degrees C, close to ambient 22.6 degrees C). This work realizes high-value utilization of waste biomass, providing a low-cost, eco-friendly solution for UAV on-board electronic systems.

Although graphitic carbon nitride (g-C3N4) is a promising two-dimensional material with good thermal conductivity, its wide bandgap and rapid charge recombination limit its direct application in photothermal conversion. In this study, an in-situ doping strategy was employed to introduce copper into the intrinsic vacancies of g-C3N4, fabricating a surface-porous 2D Cu-doped material (g-C3N4@Cu). Microstructural and spectroscopic analyses reveal that atomically dispersed Cu via Cu-N bonds significantly broadens the visible-light absorption band via the ligand-to-metal charge transfer (LMCT) effect. This mechanism enables highly efficient absorption and photothermal conversion under blue light (450nm). This novel photothermal sensitizer was then uniformly immobilized onto nitrocellulose (NC) via a solution-based approach, forming g-C3N4@Cu/NC energetic microspheres. This integrated design not only enhances interfacial adhesion but also curtails the thermal diffusion path from the photosensitizer to the NC matrix, establishing a synergistic photothermal-thermocatalytic mechanism. Consequently, the composite g-C3N4@Cu/NC achieves a photothermal conversion efficiency of over 37%. Furthermore, its laser ignition delay time is significantly reduced by approximately 30 times compared to the blank control group, demonstrating an extremely low ignition threshold. Ultimately, this study provides fundamental insights into metal-doped g-C3N4 systems and offers an effective material-design approach for integrating photosensitive and energetic materials for highly controllable optical-to-thermal responses.

Developing low-cost, flame-retardant phase change materials (PCMs) for passive building energy conservation remains a critical challenge. Here, we report a comprehensive case study on an ultra-low-cost phase change composite aerogel (P/WPA) skillfully derived from upcycled industrial waste corrugated paper. A structurally reliable, vertically aligned cellulose scaffold (WPA) is fabricated via directional freezing, followed by vacuum infiltration with disodium hydrogen phosphate dodecahydrate (DHPD) and sealing with a polydimethylsiloxane/expanded graphite (PDMS/EG) protective skin. Thermal characterizations reveal that the P/WPA composite delivers a high melting enthalpy of 189.31 J/g and exhibits a unique spatially decoupled heat transfer mechanism, combining a low through-thickness thermal conductivity of 0.48 W/(m·K) for insulation with rapid lateral heat spreading. Interfacial hydrogen bonding achieves a 43% reduction in supercooling degree (down to 16.2 °C) and ensures excellent cycling reliability (merely 3.6% enthalpy fade over 200 cycles). Crucially, outdoor engineering case tests performed under real plateau environment show that integrating P/WPA into building envelopes dramatically buffers thermal fluctuations, reducing peak indoor temperatures by 6–8 °C. Boasting a highly competitive overall manufacturing cost of ∼$0.0123/g (including processing energy overheads), this study provides a practical, sustainable, and commercially compelling case paradigm for green building energy storage.

Strain-induced crystallization (SIC) could be promoted by the presence of physical entanglement network within polymer systems with high regularity in molecular chain structure. However, such effect is not fully investigated within systems with lower chain structural regularity and inferior crystallization ability. In this study, hydrogenated nitrile butadiene rubber (HNBR) samples with varying molecular weights but share a similar acrylonitrile content of ∼37 wt% were used to investigate the influence of molecular weight on stretching orientation and SIC behaviors of HNBR by using polarized Fourier transform infrared spectroscopy (polarized FTIR) and two dimensional wide angle X-ray diffraction (2D WAXD) technique. Different chemical units within HNBR chain exhibited similar orientation degrees during stretching, implying a uniform orientation of molecular chains under strain. A positive correlation was obtained between the degree of whole chain orientation and molecular weight of HNBR. HNBR samples with Weight-average Molecular Weight (MW) of 14.6 × 104 g/mol and 32.5 × 104 g/mol could not crystallize under strain. When MW was high enough (52.7 × 104 g/mol), SIC occurred and presenting improved crystallization ability, where the crystal was composed of hydrogenated butadiene–acrylonitrile alternating copolymer segments. Higher degree of molecular chain orientation under strain induced by physical entanglement network of long-chain molecules was thought to account for the enhancement of SIC in HNBR-37.

The development of intelligent materials integrating active early fire warning and passive flame-retardant capabilities is of paramount importance for advanced fire safety. A self-powered, thermoelectric-enabled flame-retardant coating (PVB/MXene@PILs) is developed via in-situ polymerization of a halogen-free hypophosphite ionic liquid onto MXene nanosheets within a polyvinyl butyral (PVB) network. The synergistic ion-electron transport channels endow the composite with excellent low-temperature thermoelectric properties. Upon flame exposure, the coating functions as a highly sensitive temperature sensor, generating a reliable thermoelectric voltage to trigger an ultra-fast fire alarm within 4.0 s without an external power supply. Furthermore, the coating exhibited excellent passive flame-retardant performance, with the optimal PVB/MXene@PILs-4 sample achieving a maximum limiting oxygen index (LOI) of 29%, a UL-94 V-0 rating, and rapid self-extinguishment within approximately 2 s. A dual-phase synergistic mechanism drives this performance: phosphorus-containing volatiles quench reactive radicals in the gas phase, while polyphosphate intermediates catalyze a dense intumescent char layer in the condensed phase. This multifunctional coating provides a promising paradigm for the design of advanced fire safety materials.

In this paper, a new method of preparing SiO 2 Aerogel is introduced. This SiO 2 Aerogel is a composite ultra-fine glass cotton, and it is a high-efficiency and energy-saving material. First of all, a tank furnace is used to prepare clear and homogenized glass melt. Secondly, the molten liquid is treated by metal flow heating technology and high-speed airflow secondary ultra-fine fiber forming process to produce ultra-fine glass wool fibers with an average fiber diameter of 2-4 um. Thirdly, it is treated with negative pressure collection cotton process and then passes through a pendulum laying net to prepare fiber aggregate. Fourthly, use a stepper needle punching machine to obtain a fiber blanket with a specific thickness and bulk density. Fifthly, the fiber blanket is impregnated with SiO 2 Aerogel. Sixthly, send the fiber blanket into an atmospheric pressure drying oven for drying and solidification. Finally, it is treated with a double-sided aluminum foil process. Experiments have proved that it is a new material with high efficiency, energy saving, and heat preservation.

Electrically controlled solid propellants (ECSP) have attracted extensive attention due to the tunable burning rate. The burning rate of ECSP determines the applying background of propellants and rocket engine structural design. Herein, an ECSP named ECSP was prepared using HAN as the oxidizer, PVA as the binder and self-developed electric controlled PCH as the fuel. It was investigated that the influence of pressure, initial temperature and voltage on the burning rate of the propellant. The results indicate that the pressure index n of ECSP is 0.36, the temperature sensitivity coefficient σP is 0.005 K-1. Under certain conditions, the burning rate of ECSP varies linearly with voltage, and the maximum regulation range is higher than 39 %. Fitted the burning rate equation of ECSP with the voltage parameter based on Vielle’s burning rate equation, the consistency between the actual chamber pressure of the ECSP in the prototype and the predicted pressure by the burning rate equation was verified.

Hydrophobizing hydrophilic aerogels is both necessary and complex, as the introduction of hydrophobic modifiers often compromises key properties, such as density and mechanical performance. In this study, we demonstrate a self-cross-linking hydrophobic flame-retardant fluorescent aerogel without the use of external modifiers. We explore the chemical reaction between a maleic anhydride copolymer and ammonia, leading to a ring-opening reaction that interacts with the carboxyl and hydroxyl groups of ammonium alginate. This process enables hybrid cross-linking between molecular chains without the need for additional cross-linking agents. Furthermore, it facilitates a significant hydrophilic-to-hydrophobic transition throughout the cross-linking process. The resulting aerogels exhibit enhanced mechanical and hydrophobic properties, withstanding up to 80% compressive deformation without visible cracking and showing resilience. The contact angle of the aerogel surface is 131°, indicating effective self-hydrophobicity. This research also explores the structural changes occurring during the cross-linking process and examines how different raw material ratios influence overall performance. In addition, the aerogels demonstrate both flame retardancy and fluorescence, enhancing their versatility. This approach offers a strategy for creating polymer aerogels with high flame retardancy and hydrophobicity without relying on external modifiers.

Durable multifunctional textiles with advanced protective performance are increasingly crucial for maintaining stability in complex and harsh environments. However, the prevalent use of disposable synthetic surface treatments poses an intractable challenge to the circular economy focused on sustainability. In this study, we introduce an innovative biomimetic sustainable silk textile that is stable in harsh environments and offers high flame retardancy, antibacterial, and anti-mildew properties through a simple yet effective surface treatment strategy. This treatment leverages a specially designed aromatic polyorganosiloxane with quaternary ammonium structures, capable of programmable, robust, and stimulus-responsive reversible cation-π adhesion. The resulting strong water-insensitive cohesive energy from biomimetic cation-π interactions between aromatic and cationic moieties ensures that the multifunctional textiles exhibit excellent long-term durability, even under challenging conditions such as underwater, in saltwater, and in acidic or alkaline solutions. Moreover, the reversible reconstruction of cation-π adhesion allows for on-demand surface treatment recycling, achieving a 100% recycling rate. This study offers a new approach to creating smart and multifunctional textiles that combine sustainability with robust performance in harsh environments.

Aluminum particles have become one of the essential fuels in solid propellant technology. However, the agglomeration of Al particles in combustion significantly reduces the combustion efficiency of propellants. For improving the combustion efficiency of aluminum particles, CuTFA is grown in-situ on the surface of aluminum particles and synthesized the composites fuel, named Al@CuTFA. Morphological analysis reveals that CuTFA is formed as the sheet-like structure coated on the surface of aluminum particles. The Al@CuTFA demonstrates catalytic activity in the thermal decomposition of ammonium perchlorate (AP). Furthermore, comparing with the aluminum particles, the burning rate of Al@CuTFA mixed with AP increases from 173 mm/s to 257 mm/s, attributed to the catalytic effect of Cu(II) in CuTFA on aluminum combustion. In addition, Al@CuTFA composites can effectively destroy the Al2O3 layer and mitigating the agglomeration of aluminum particles in the combustion of solid propellant. The metal fuel of solid propellant replaces the aluminum particles with Al@CuTFA, and particle sizes D50 of its condensed product is reduced from 64.976 mu m to 31.303 mu m. Thus, constructing the bifunctionalized Al@CuTFA composites is an effective strategy to improve the combustion performance of solid propellant.

Transient electronics is a versatile tool that finds applications in various fields, including medical biology, environmental protection, and data information security. In the context of data protection, the traditional passive degradation transient mode is being replaced by the active destruction mode, which features a short self-destruction time and provides greater resistance to recovery. This article presents an overview of recent progress in transient electronics, assessing the benefits and suitability of varying transient mechanisms. The article also analyses the influence of transient electronics on military security while emphasizing the advantages of implementing energetic materials. Besides, the article introduces energetic transient devices and evaluates their ability to support the autonomous operation of transient electronic devices.

Flammable ionic liquids exhibit high conductivity and a broad electrochemical window, enabling the generation of combustible gases for combustion via electrochemical decomposition and thermal decomposition. This characteristic holds significant implications in the realm of novel satellite propulsion. Introducing a fraction of the electrical energy into energetic ionic liquid fuels, the thermal decomposition process is facilitated by reducing the apparent activation energy required, and electrical energy can trigger the electrochemical decomposition of ionic liquids, presenting a promising approach to enhance combustion efficiency and energy release. This study applied an external voltage during the thermal decomposition of 1-ethyl-3-methylimidazole nitrate ([EMIm]NO3), revealing the effective alteration of the activation energy of [EMIm]NO3. The pyrolysis, electrochemical decomposition, and electron assisted enhancement products were identified through Thermogravimetry-Differential scanning calorimetry-Fourier transform infrared-Mass spectrometry (TG-DSC-FTIR-MS) and gas chromatography (GC) analyses, elucidating the degradation mechanism of [EMIm]NO3. Furthermore, an external voltage was introduced during the combustion of [EMIm]NO3, demonstrating the impact of voltage on the combustion process. (c) 2025 China Ordnance Society. Publishing services by Elsevier B.V. on behalf of KeAi Communications Co. Ltd. This is an open access article under the CC BY-NC-ND license (http://creativecommons.org/ licenses/by-nc-nd/4.0/).

The injection molding of ultra-high molecular weight polyethylene (UHMWPE) large industrial products has always been a significant challenge. This study demonstrated that the addition of bimodal polyethylene (BPE) can reduce the melt viscosity of UHMWPE, enabling the injection molding of UHMWPE products with highperformance, large size, and complex shapes. Detailed analyses including microbeam wide-angle X-ray diffraction (WAXD)/small-angle X-ray scattering (SAXS), differential scanning calorimeter (DSC), and scanning electron microscope (SEM) were conducted to investigate the crystal structural differences across various regions of UHMWPE products with different BPE contents. This study revealed that those products with low BPE content exhibited larger lamellar crystal sizes and higher tensile strength, albeit with poor microstructure uniformity, resulting in low elongation at break. Conversely, products with high BPE content had more uniform microstructures but low degrees of crystal perfection, significantly improving elongation at break. Impact performance tests revealed that adding BPE did not damage the mechanical properties of UHMWPE, showing an ultra-high impact strength of 500 kJ/m2. Furthermore, this study identified the significant effect of the complex flow field and molecular weight fraction of BPE on the crystal structure of the products. At low BPE concentrations, the low molecular weight portion of BPE predominated in the plasticizing effect during injection mold. Under weak flow conditions, this increased molecular chain relaxation in UHMWPE, making it difficult to maintain the oriented structure. Conversely, strong flow conditions promoted the formation of the oriented structure. However, at high BPE concentrations, the high molecular weight portion of BPE predominantly hindered the movement of UHMWPE, resulting in chain entanglement that does not improve significantly. In this context, the differences in the injection-molded samples under weak and strong flow conditions are minimal.

In this paper, by utilising molecular dynamic simulations, profiled carbon nanotubes (CNT), represented by CNT containing bead and spiral structure, were built from warping graphene layers with carefully introduced defects. The tensile behaviour of profiled CNTs, pulling and shock response of profiled CNTs within the polyamide matrix were investigated and compared to the corresponding conventional CNT. The result indicates that as mechanically interlocked with the matrix, profiled CNT could effectively relieve the stress concentration during load transfer by distributing the stress into a larger part of the matrix. In this case, a more efficient load transfer could be achieved, thus contributing to the mechanical performance of the composite without modification of the chemical structure. However, the profiling geometry, which is shaped by defects, will introduce stress concentration within the profile CNTs when subject to a tensile load. The stress concentration may not only deteriorate the tensile performance of CNTs, such as ultimate load at break and modulus but also result in an earlier deformation. In this case, care should be taken during the design phase of the profiled CNT. For shocking responses, profiled CNTs were capable of constraining the local chain move thus contributing to the integrity of the composite system during shockwave propagation.

Achieving both super toughness and flame retardancy in polylactic acid (PLA) materials hinges on resolving the interface compatibility issues between flame retardants, toughening agents, and PLA, as well as overcoming potential antagonisms between these components. Here, we present an approach employing hyperbranched structures to simultaneously enhance the toughness and flame retardancy of PLA materials. Our strategy involved the reactive blending of PLA with a quaternary bio-based phosphorus-containing copolyester (PPE) featuring side hydroxyl groups and hexamethylene glycidyl cyclotriphosphazene (HGCP). The multi-epoxy groups of HGCP reacted with the hydroxyl and carboxyl groups present in PPE and PLA, resulting in the formation of hyperbranched PLA-PPE copolymers. The hyperbranched copolymers provided great interfacial compatibilization and low viscosity, synergistically promoting the melt-dripping flame-retardant mechanism facilitated by PPE, aiding in the rapid removal of heat and combustible material from the pyrolysis zone. Consequently, the PLA/PPE/ HGCP blends exhibited super toughness, achieving a maximum notched impact strength of 70.2 kJ/m2. Additionally, the blends demonstrated a 27 % LOI and can pass the UL-94 V-0 rating. Moreover, all the blends are biodegradable in a Proteinase K solution. This research underscores the efficacy of utilizing hyperbranched structures as a promising strategy for the development of PLA materials with simultaneous enhancement of processability, toughness, and flame retardancy.

Carbon materials play a pivo tal role across various advanced applications, yet their synthesis traditionally necessitates inert atmospheres to avert oxidation at high temperatures, thus inflating production costs and resource utilization. Achieving precision synthesis of functional porous carbon materials via air-pyrolysis remains a formidable challenge. Herein, a streamlined, one-step lava-like carbonization approach is introduced enabling the fabrication of porous carbons boasting tailored morphologies (0-3D), elevated specific surface areas (540.7-1047.6 m2g(-)(1)), heteroatom doping, and commendable carbon yields (20-39.1%) through direct pyrolysis within an air environment. Leveraging recyclable boric acid as a reaction medium, a lava-like flowing protective barrier above 170 degrees C is engendered that spontaneously creates an oxygen-free-like milieu devoid of high pressure or intricate procedures. This boron-containing lava serves dually as a template and chemical activator, facilitating pore formation and catalyzing porous carbon production. Notably, the method accommodates a spectrum of carbon sources, encompassing sugars, proteins, graphene oxide, and their metal mixtures. The resultant morphologically customizable carbons exhibit excellent performance in areas as diverse as microwave absorption and electrocatalysis. This work pioneers a novel pathway for large-scale precision synthesis of high-quality carbon materials via air-pyrolysis under mild conditions.