Supramolecular ferroelectrics, which integrate the dynamic tunability of supramolecular chemistry with the functional attributes of ferroelectrics, hold considerable promises for various applications in flexible wearable electronics, next-generation information storage and advanced sensing and detection. Herein, this review initially summarizes recent advances in ferroelectric systems constructed from supramolecular macrocycles and cage-type building blocks and presents a systematic analysis of the interaction principles that underpin ferroelectricity enabled by supramolecular design. Emphasis is placed on the methodologies employed to break symmetry and establish long-range polar order in supramolecular assemblies. Additionally, strategies for enhancing ferroelectric performance through supramolecular assembly, chemical modification, and solvent-/guest-induced engineering are summarized and analyzed. Furthermore, key challenges in performance modulation and device integration are discussed from both fundamental and applied perspectives, and forward-looking insights into the use of supramolecular ferroelectrics in multifunctional systems are offered. By clarifying current advances and outlining future directions, this review aims to lay a solid foundation for the continued development and practical implementation of supramolecular ferroelectrics in next-generation functional materials and devices.

Achieving silicone elastomers that combine high toughness with recycling stability remains a persistent challenge, as conventional toughening strategies enhance energy dissipation at the expense of reversible network reconfiguration for stable reprocessing. Here, we address this challenge by engineering a dynamically arrested bicontinuous phase within a silicone elastomer. Grafting long perfluoroalkyl chains onto a polysiloxane backbone induces phase separation, forming a continuous fluorinated phase for efficient energy dissipation alongside a complementary silicone phase that preserves elasticity. The architecture is arrested by a dual dynamic network of beta-amino ester covalent bonds and hydrogen-bonding segments, which suppress phase coarsening while enabling thermal reprocessing without degrading intrinsic phase structure. The resulting elastomer achieves an exceptional toughness of 29.3 MJ m-3 and an elongation of 1510%, while exhibiting outstanding recycling stability, with properties well retained after five reprocessing cycles. By simultaneously resolving the conflicting demands of toughness and recycling stability, this work establishes a viable pathway toward recyclable, high-performance silicone rubber materials with industrial relevance.

Achieving monodisperse droplets from high-viscosity, shear-thinning polymeric fluids presents a fundamental hydrodynamic challenge, as viscous damping and non-Newtonian rheology modify the growth of capillary-driven breakup instabilities. This work reports a vibration-assisted active control strategy to regulate the droplet formation process. Three-dimensional direct numerical simulations reveal that vibration induces vortices near the necking region, enhancing shear rates and reducing apparent viscosity to ensure rupture. A stability-based interpretation indicates that the optimal frequency aligns with the maximum growth rate of the instability. A unified flow regime map based on compound dimensionless groups is established to predict the boundary between the uniform droplet and random droplet regimes. Furthermore, a dimensionless scaling law is developed to characterize droplet size. Compared to non-vibrated conditions, the active vibration reduces the coefficient of variation of microspheres by a factor of up to 7.8. This study provides a methodology for the fabrication of uniform polymeric droplets and microparticles.

This study systematically investigated the interfacial lubrication mechanism of polytetrafluoroethylene (PTFE) under various loads in a liquid oxygen (LO2) environment using reactive molecular dynamics simulations. The results demonstrate that LO2 forms a lubricating protective layer at the friction interface, thereby effectively reducing interfacial adhesion and friction. Furthermore, the introduction of LO2 reduces the temperature of the tribological pair, improves the shear stress distribution, inhibits crystal structure damage, and significantly enhances the diffusion capability of PTFE molecules. Notably, the most significant improvement in lubrication performance due to LO2 is observed at a low load of 0.7GPa, with an average friction reduction of 74.23%.

A microscopic model with a high degree of polyimide (PI) pore structure reproduction was constructed using the quartet structure generation set method and slicing technique. Based on finite element method, a visual simulation of PI porous models with different porosities was performed. The migration characteristics of lubricating oil within models of varying porosities under the influence of centrifugal force, as well as the impact of porosity on capillary oil absorption properties, were thoroughly analyzed. Results shown that the increase in porosity leaded to a rising trend in the lubricating oil content within the porous PI model, indicating that under the influence of centrifugal force, the migration amount of lubricating oil increases with the increase in porosity. When considering only capillary forces, the volume fraction of lubricating oil and the oil level line within the porous PI model initially rised rapidly and then tended to stabilize as porosity increases. This demonstrated that the increase in porosity significantly promoted the capillary oil absorption process. The primary reason is that the increased porosity allows more pores to participate in oil absorption through capillary forces, thereby increasing the oil content. However, when the porosity is too high, pore merging occurs, which weakens the capillary force effect.

Laser beam powder bed fusion (LPBF) is a widely used metal Additive Manufacturing (AM) process but faces safety and cross-contamination risks from loose powders. Metal Additive Manufacturing using Powder Sheet (MAPS) addresses these issues by using metal particles bound in polymer sheets, reducing powder handling hazards. However, powder sheet recycling remains unexplored. This study investigates the effects of recycling on the thermal, chemical, and mechanical properties of recycled SS304 powder sheets and their impact on MAPS-printed parts. Thermogravimetric analysis showed that 50 % and 100 % recycled sheets retained over 95 % metallic content and thermal stability comparable to fresh sheets. Mechanical testing revealed that 50 % recycled sheets achieved the highest tensile strength and ductility due to a synergistic microstructure from mixing fresh and recycled particles. MAPS-printed components using recycled sheets reached >99.80 % relative density, with consistent microhardness and internal microstructure compared to parts from fresh sheets. These results demonstrate that recycling powder sheets preserves or enhances feedstock performance while improving sustainability and material efficiency, supporting MAPS as a scalable, safer, and environmentally responsible alternative for metal AM.

The efficient loading of PtCo bimetallic materials on hollow carbon nanofibers synergizes to facilitate the methanol oxidation reaction at the anode of DMFCs.

High-precision bearings are critical in precision CNC machine tools, aerospace systems, and instrumentation. Their dominant failure mode has shifted from subsurface-originated fatigue to surface-originated damage, with contaminant particle intrusion becoming a key life-limiting factor. However, the underlying mechanisms remain unclear, as existing research predominantly focuses on subsurface issues. Therefore, this work systematically investigates the damage mechanism of GCr15 bearing steel raceways under particle indentation using Voronoi finite element method and experiments. A Voronoi finite element model accounting for the random distribution of metal grains was established to simulate the indentation process induced by particles (0.20 mm-1.00 mm in diameter) under loads of 200-350 N. Results indicate that for a given particle size, indentation depth increases with load. Specifically, increasing the load from 200 N to 350 N raised the indentation depth by 133.28 %-174 % and residual stress by 35.38 %-53.42 %. Under constant load, indentation depth decreases with increasing particle size. As diameter increased from 0.20 mm to 1.00 mm, depth reduced by approximately 67.92 %- 69.77 %. The deviation between simulation and experimental results was less than 8.78 %, validating the effectiveness of the results. Further analysis reveals that the maximum residual tensile stress is concentrated at the indentation edges, identifying them as the primary sites for micro-crack initiation. This work clarifies the effects of load and particle size on surface damage and stress distribution, elucidating the mechanism of particleinduced surface damage. The findings offer a theoretical basis for anti-surface-damage design and longevity prediction of high-precision rolling bearings.

Multi-point contact ball bearings are widely used in many fields such as aircraft development, high-speed rail, new energy and others because of their unique multi-race structure. However, due to excessive contact angle and multi-point contact status, the bearings are prone to thermal failure at high speeds, thus limiting the further expansion of their applications. To this end, the contact feature among the ball and raceways is investigated, a number of the relative positional relationships and velocities are further defined. Based on the theory of Hertzian and elastohydrodynamic lubrication, the govern equations of lubricant contact of the ball is established. Considering the dynamic effect of the cage, a common dynamic model of multi-point contact ball bearing is further established. Its predicted values are in good agreement with the experimental test values. On this basis, the spinning motion of each raceway under typical operating conditions is investigated. Some interesting results can be founded as follows: when the bearing is operated under purely axial load, there may be three contact points on the ball and a large spinning motion on one of the raceways. With the heavier axial load exerted on the bearing, this spinning motion would disappear as the ball moves out of contact with the raceway. Once the bearing is subjected to radial load, two contact points, three contact points and four contact points may occur sequentially for each revolution cycle of the ball. A maximum spinning on one raceway is generated when the ball is in the four-contact status. Crucially, the smaller initial contact angle helps to suppress the spin component on each raceway of the bearing at high speeds. This research provides theoretical guidance for the development of high-speed multi-point contact ball bearings.

The catalytic efficiency of naphthalene propylation has always been severely limited by the difficulty in precise regulation of acidic sites and sluggish reaction kinetics. Herein, we synthesize a series of transition-metalmodified hierarchical mordenites by alkaline desilication and subsequent mild acid leaching, followed by the incorporation of different transition metals through ion exchange. The alkaline-acid treatment creates hierarchical porous architecture to facilitate rapid intracrystalline diffusion, while metal ion exchange allows for precise modulation of the acidity for the selective propylation of naphthalene to 2,6-diisopropylnaphthalene (2,6-DIPN). Co modified hierarchical mordenite (IE-Co-BA-MOR) exhibits the optimal catalytic performance for naphthalene propylation with high naphthalene conversion of similar to 88.7%, and 2,6-DIPN yield of similar to 30%. IE-CoBA-MOR retains high crystalline structure, where the single Co atoms replace the H atoms and coordinate with O to form O-Co-O. Exchanged Co2+ reduces surplus Lewis acidity while retaining channel Bronsted sites (higher B/L than other transition-metal-modified MORs). In contrast, with replacing ion exchange by impregnation, CoOx species are predominantly formed on the external and mesopore surfaces of MOR (IW-Co-BA-MOR), resulting in suppressed Bronsted sites and strong external Lewis centers. Thereby, IW-Co-BA-MOR catalyst exhibits superior catalytic activity compared to the pristine MOR, yet its performance is surpassed by that of IE-Co-BA-MOR sample.

As a critical component of high-end equipment such as aero-engines, the lubrication performance of cylindrical roller bearings directly impacts the operational reliability of the equipment. To thoroughly reveal the variation patterns of fluid drag loss within the bearing cavity under different rotational speeds and clearance conditions, this study constructs a high-precision fluid dynamics model of cylindrical roller bearings based on fluid dynamics theory. By introducing a rotating coordinate system, the motion relationships between the bearing components are accurately described. On this foundation, a research method for internal fluid drag loss in rolling bearings based on Computational Fluid Dynamics (CFD) is proposed, systematically quantifying the distribution characteristics of fluid drag loss within the bearing cavity. By varying key parameters such as rotational speed, pocket clearance, and guide clearance, the influence of these factors on fluid drag loss is thoroughly investigated, providing a scientific basis for the optimization of lubrication design in cylindrical roller bearings. This research offers essential theoretical guidance and support for bearing lubrication design and the enhancement of bearing operational reliability.

Piezoelectric materials can efficiently convert widely available mechanical energy to usable electrical energy or chemical energy, which represent a type of promising sustainable materials and is worth being extensively explored. Covalent organic frameworks (COFs), with their finely tunable structures and properties, have emerged as exciting materials for piezoelectric applications. This review aims to discuss the strategy for enhanced piezoelectric properties of COFs and the applications of COFs in the piezoelectric field, including piezocatalysis and piezoelectric nanogenerators. Then, the effect of pressure on the structure of COFs is introduced, which may provide new perspectives for the design of COFs in piezoelectricity. The review concludes that COFs offer a versatile platform for developing advanced piezoelectric materials, with potential in wide range of applications. The insights provided in this review are hoped to guide the direction of future research in the field of COF-based piezoelectric materials. (c) 2026 Published by Elsevier B.V. on behalf of Chinese Chemical Society and Institute of Materia Medica, Chinese Academy of Medical Sciences.

High-performance printed circuit board (PCB) substrates require polymer matrices combining high thermal stability, mechanical robustness, and low dielectric constant. However, conventional polycyanurate resins suffer from intrinsic brittleness owing to highly crosslinked triazine networks, limiting their broader use in advanced PCB substrates. Herein, we developed nanophase-separated linked interpenetrating polymer networks (LIPNs) based on bisphenol A dicyanate (BADCy) and ethynyl phenyl azophenol-biphenylene resins (EPABNs). By regulating nanophase-separated domains (Rm) and interfacial thickness (lint), the toughness of the LIPNs was significantly improved. The LIPNs were constructed via a gradient temperature curing protocol, during which iminocarbonate linkers formed in situ to chemically bridge the networks and suppress macrophase separation. By tuning the linkers and ethynyl content, the LIPNs exhibited a transition from agglomerated domains to a highly interconnected bicontinuous morphology, accompanied by systematic changes in lint and segmental dynamics. Dynamic mechanical analysis (DMA) and small-angle X-ray scattering (SAXS) reveal balanced interfacial confinement and coordinated segmental dynamics in the optimized LIPN. As a result, the optimized polycyanurate/ethynyl-resin LIPN achieved a high glass transition temperature (Tg) of 274 degrees C, a flexural modulus of 3.2 GPa, and an impact strength of 30 kJ m-2. Furthermore, basalt fiber reinforced polymer composites (BFRPCs) based on this LIPN exhibited a low dielectric constant of 2.84 at 1 MHz and a high flexural strength of 566 MPa. The reduced dielectric constant is attributed to the dense interconnected network, which restricts polar-group mobility and mitigates moisture-induced interfacial polarization. This work highlights interphasecontrolled nanophase separation as an effective strategy for constructing toughened polycyanurate LIPNs for high-performance PCB substrates.

Hierarchical porous N-doped carbon nanofibers incorporating Ni nanoparticles (Ni@HPCNF) were synthesized via an electrospinning and NH4HCO3-assisted co-pyrolysis strategy. The unique 1D porous architecture and graphitic carbon encapsulation provide abundant active sites and accelerate mass and electron transfer. Consequently, Ni@HPCNF exhibits superior methanol oxidation performance, delivering a high current density of 27.6 mA cm-2 with excellent long-term stability. In situ impedance spectroscopy confirms its exceptionally fast reaction kinetics. This work presents a low-cost, eco-friendly strategy for designing highly efficient carbon-based electrocatalysts.

Due to the high rotational speed, high temperature, and high reliability requirements of commercial aviation engines, the lubrication design of hot-end cylindrical roller bearings has become critical. To reveal the lubricant oil flow characteristics inside the bearing cavity under different rotational speeds and clearances, this study aims to optimize and enhance the oil spray lubrication effect of the bearings. A high-precision hydrodynamic model of cylindrical roller bearing was constructed based on the fluid dynamics theory. Moreover, by defining the rotational coordinate system, the motion relations of the bearing components were described. Subsequently, the oil-air flow in the bearing cavity was numerically solved using the Volume of Fluid (VOF) model and Semi-Implicit Method for Pressure Linked Equations (SIMPLE) to obtain the distribution of the oil-air two phases. The macroscopic motion characteristics under different working conditions were studied by varying the rotational speed, pocket clearance, and guide clearance. The lubrication performance of the bearings was evaluated based on the pressure field, velocity field, and oil phase distribution, highlighting the influence of rotational speed and clearance on the cylindrical roller bearings, ultimately optimizing the lubrication design. The findings offer crucial theoretical guidance for the lubrication instruction of bearings, which is vital for ensuring their high reliability.

Polyurethanes (PU) have been widely utilized in various advanced sectors, from insulation, elastomers, adhesives, and coatings to civil engineering materials. However, within the framework of the circular economy and in light of the urgent need to reduce the environmental impact of plastics, technologies have been designed, assessed, and exploited for the recycling and upcycling of discarded PU thermosets, which are chemically crosslinked and difficult to reprocess. This review comprehensively examines the current state of PU thermosets, discusses various recycling technologies, and highlights emerging upcycling strategies that promise to transform low-value waste into high-performance products. By also addressing the design of smart PU derivatives featuring reversible covalent and non-covalent bonds, this paper provides a detailed analysis of how innovative material design can promote a more sustainable and circular life cycle for PU thermosets. Finally, the review offers perspectives on future research directions and industrial implementation of recycled/upcycled PU thermosets, providing readers with some perspectives about the possible future developments.

The rated dynamic load is one of the key parameters for measuring the dynamic load-carrying capacity and service life of radial spherical plain bearings. To accurately and rapidly determine the rated dynamic load of radial spherical plain bearings, this paper proposed a universal theoretical calculation model for the rated dynamic load of radial spherical plain bearings, based on the Archard wear theory and the displacement interference field model. The proposed model comprehensively considered the effects of bearing clearance, structural features, and operating mode on the magnitude of the rated dynamic load. By comparing the results from the theoretical model with existing data from studies, the accuracy of the model was demonstrated. Case studies with different bearing clearances show that, in addition to material and structural parameters, clearance is also a key factor that affects the dynamic load-carrying capacity of spherical plain bearings. The rated dynamic load decreases as the clearance increases. This theoretical model exhibits extensive applicability and can be extended to the design and selection of non-standardized spherical plain bearings, providing a crucial theoretical foundation for performance optimization and engineering applications of spherical plain bearings.

Compared to Newtonian fluids, the flow and heat transfer behavior of non-Newtonian viscoelastic polymer solutions are more complex. In this study, a numerical investigation is carried out to analyze the flow dynamics and heat transfer characteristics of viscoelastic fluids in a stirred reactor. The Phan-Thien–Tanner viscoelastic constitutive model is employed to accurately capture the complex rheology of polymer solutions. This study focuses on exploring the potential influence of the inertial Reynolds number (Re, denoted by impeller rotational speed N) and fluid elasticity (denoted by relaxation time λ) on enhancing flow mixing and heat transfer. Results indicate that heat transfer performance improves with increasing rotational speed and relaxation time. Under sufficient inertia, increased elasticity leads to greater deformation of long-chain polymer molecules, triggering elastic instability phenomena. At the critical relaxation time of λ = 0.1, two distinct flow regimes are observed. Increased elasticity triggers elastic turbulence, which effectively enhances fluid mixing and convective heat transfer within the reactor. Under highly elastic conditions (λ > 0.1 s), the Nusselt number (Nu) exhibits non-monotonic temporal behavior. Dimensionless analysis further demonstrates that viscoelastic fluids achieve superior heat-transfer efficiency relative to Newtonian fluids, with Nu enhanced by 7.16% and 22.58% at Re = 405 and Re = 675, respectively, under highly elastic conditions. Furthermore, the optimized frame-type combined impeller exhibits excellent performance in the flow and heat transfer processes of viscoelastic fluids. The present work is conducive to the development and optimization of high-efficiency heat transfer reactors for polymerization processes.

High-performance elastomers always suffer from the trade-off between the ability of self-healing and mechanical stiffness. Here we report a hierarchical, synergistic hydrogen-bonding design that overcomes this trade-off. By integrating quadruple hydrogen bonds with moderately dynamic hydrogen-bond clusters within the hard domains of polyurea, we create a dual-dynamic, decoupled phase architecture that simultaneously imparts rigidity and enables reversible molecular reconfiguration. This interplay of strong and dynamic interactions generates robust hard domains that reinforce mechanical strength while preserving rapid, thermally activated self-healing. The resulting polyurea exhibits near-complete recovery of mechanical performance (approximate to 100% at 80 degrees C after 8 h) together with a high Young's modulus of 24.2 MPa. This work demonstrates a rational strategy to reconcile the conflicting demands of self-healing and stiffness in polymeric materials through a hierarchical synergistic hydrogen-bonding system.