Search Results (1,129)

To develop eco-friendly and highly efficient fruit and vegetable preservation materials, this study uses the multi-gradient micro–nano roughness structure and bioactive properties of orange peel as a biomimetic model, aiming to construct a functional film with a unique dual mechanism of physical barrier protection and active preservation. Using soft etching and secondary transfer methods, with polydimethylsiloxane as an intermediate template, and through a repeated freeze–thaw cross-linking process, a polyvinyl alcohol system containing orange peel essential oil was cast to successfully prepare a biomimetic film featuring the micro–nano hierarchical structures found on the surface of orange peel. The study indicates that the biomimetic film accurately replicates the cross-scale hierarchical structures of the natural orange peel surface. Structure–property relationship analysis revealed that the biomimetic film containing 15% orange peel essential oil exhibited the optimal comprehensive performance, characterized by significantly enhanced tensile strength and improved water vapor barrier properties, while demonstrating effective antioxidant and regulated antibacterial activities. Crucially, compared to conventional flat active films, the replicated multi-scale surface roughness provides clear functional advantages by physically optimizing interface properties and cooperating synergistically with the chemical vapor release of the essential oil. Blueberry preservation experiments confirmed that the biomimetic film successfully maintains fruit firmness, vitamin C, and anthocyanin content, while suppressing weight loss and decay rates. This study simulates the microenvironmental control mechanisms of orange peel, highlighting the scientific novelty of structural–chemical synergistic design for advanced functional packaging. Full article

The extensive use of plastics in everyday life has exerted a significant influence on the environment, with the release of micro- and nanoplastics posing even greater ecological threats. Plastic contamination, particularly in these smaller forms, has emerged as a pressing environmental concern due to its persistence, bioaccumulation, and potential hazards. Traditional treatment systems are generally ineffective at removing such micro- and nano-scale complex pollutants. Recently, micro- and nanofiber-based materials have emerged as promising candidates due to their large surface area, porous structure, and adjustable functionality, enabling efficient adsorption, filtration, and photocatalytic degradation. The term micro/nanofibers in this study encompasses both electrospun nanofibrous membranes and nanofiber-based functional layers or additives incorporated into pre-existing membrane structures for performance enhancement. The incorporation of photocatalysts enables these materials to promote photocatalytic oxidation, degrading plastics into smaller, less toxic compounds. This paper outlines recent progress in developing micro- and nanofiber systems for environmental remediation, highlighting their design approaches, removal mechanisms, and multifunctional capabilities. Ultimately, the discussion explores emerging directions, existing limitations, and future opportunities, highlighting how these advanced materials can contribute to sustainable and efficient pollution control strategies. Full article

To address prevalent industrial challenges, including the high cost of fabricating microstructures via photolithography and 3D printing, impurity residues easily generated by conventional physical/chemical pore-forming techniques, and the limited sensitivity of regular capacitive sensors, this paper innovatively proposes an integrated low-temperature in situ gas foaming strategy using ammonium bicarbonate for the fabrication of porous TPU-based ionic gels. Relying on the complete gaseous decomposition property of ammonium bicarbonate upon heating, a three-dimensionally interconnected continuous porous network is spontaneously constructed inside the polymer matrix. Thermoplastic polyurethane (TPU) is selected as the continuous polymer phase, and [EMIM][TFSI] imidazolium ionic liquid is blended as the ion source to synthesize composite ionic gel substrates. A PDMS composite slurry filled with graphene is employed to prepare flexible substrates, followed by low-temperature oxygen plasma surface modification to introduce polar functional groups such as hydroxyl and carboxyl onto electrode surfaces. A standard sandwich-structured ionic pressure sensor with the configuration of “top modified electrode—porous ionic gel dielectric layer—bottom modified electrode” is finally assembled. The porous framework and modified electrodes constitute a dual synergistic enhancement system: the porous structure markedly reduces the equivalent elastic modulus of the gel and improves its compressive deformation capacity; polar-modified electrodes optimize the interfacial compatibility between electrodes and gels, shorten ion migration paths and lower interfacial contact resistance. Systematic calibration of multiple batches of parallel samples reveals that the as-fabricated sensor achieves a high sensitivity of 25.3 kPa⁻¹ across the full measuring range from 0 to 1000 kPa with a linear fitting coefficient R² = 0.992. The loading response time and unloading recovery time of the device are 60 ms and 80 ms respectively, with a performance degradation of less than 3% after 1000 consecutive loading–unloading cycles, featuring low hysteresis error and excellent signal repeatability. Multi-scenario in vivo wearable tests on human subjects verify that the device can precisely capture subtle fluctuations of radial artery pulse and periodic laryngeal deformation during swallowing, distinguish characteristic waveform patterns of various English words according to differences in vocal cord vibration, and accurately detect bending motions when attached to finger joints. The entire fabrication process adopts common chemical raw materials and standard laboratory equipment without expensive micro-nano processing facilities, featuring convenient raw material procurement and high process fault tolerance, which enables large-area coating-based mass production. This work delivers a novel technical route for the low-cost large-scale production of high-performance ionic flexible sensors and bears significant industrialization reference value for applications in wearable medical monitoring, bionic robotic electronic skin, flexible human–machine interactive touch panels and other related fields. Full article

Maintaining wellbore stability in deep and ultra-deep formations demands plugging agents capable of sealing nano- to micro-scale pores under high-temperature conditions. A core–shell nano-plugging agent (CSP) was synthesized via emulsion polymerization using KH-570-modified nano-SiO₂ as the rigid core and a poly(styrene-co-butyl acrylate-co-methyl methacrylate) terpolymer as the deformable shell. CSP particles had a mean diameter of 196.5 nm (polydispersity index, PDI = 0.183) and an onset decomposition temperature of 342 °C. Compatibility tests at 180 °C confirmed that 3 wt% CSP caused no adverse changes in the rheology or emulsion stability of the oil-based drilling fluid (OBM). At 180 °C, CSP reduced the high-temperature high-pressure (HTHP) filtrate loss by 64.4% and the permeability plugging apparatus (PPA) filtrate loss by 66.1%. Sand-disk tests elevated the breakthrough pressure from 1.5 to 9.2 MPa. Core displacement on sandstone cores achieved a plugging rate of 98.30%, and pressure transmission tests on natural shale cores extended the 50% equalization time by 7.8-fold. Comparative evaluation confirmed that the core–shell architecture consistently outperformed nano-SiO₂ alone, polymer alone, and their physical blend. Low-temperature N₂ adsorption provided direct evidence of pore sealing, with the treated-shale Brunauer–Emmett–Teller (BET) surface area and total pore volume reduced by about 62% (12.6 to 4.8 m²/g and 0.0325 to 0.0121 cm³/g, respectively). Scanning electron microscopy of the shale surface before and after treatment further provided direct visual evidence of pore sealing, showing the open, porous matrix being converted into a dense, compacted filter cake. Filter-cake thickness measurements are consistent with a proposed three-stage plugging mechanism—bridging, deformation filling, and thermal compaction—driven by the complementary roles of the rigid core and the deformable shell. These findings indicate that CSP merits further evaluation as a high-temperature plugging agent for wellbore stabilization in deep shale formations. Full article

The rapid growth of electric vehicles and electrified systems has increased the risk of bearing failures due to combined mechanical and electrical stresses. This study investigated the performance of hexagonal boron nitride nanoparticle-enhanced lithium grease under electrified conditions. Experiments based on a Taguchi L9 orthogonal array were conducted on deep groove ball bearings using a full-scale test rig at 1200 rpm with varying loads (100–300 N), currents (6–10 A), and hBN concentrations (0.1–1 wt.%). The tribo-electrical performance of nano-enhanced grease was compared with the base grease and commercial grease. It was observed that the base grease exhibited superior performance with a lower current flow, reduced vibration, and minimal surface degradation. In contrast, the hBN-enhanced grease exhibited inferior tribo-performance, with high vibrations and surface damage in electrified conditions. The surface analysis revealed features morphologically similar to white etching areas and micro-pitting. The FTIR results indicated grease degradation, while ICP-OES confirmed higher wear debris generation in the commercial and hBN-added greases. The present work indicates that additives like hBN nanoparticles do not necessarily improve performance under electrified conditions, making it important to consider the type of additives to be added during lubricant formulation. Thus, the findings emphasize the importance of lubricant formulation for controlling electrically induced bearing failures and provide insights for developing advanced greases for electric machinery applications. Full article

The influence of BN particle size on lithium grease performance was systematically compared among a base grease (Li), a micro-BN (3 µm, 0.1 wt%) modified grease (Li + 0.1% mBN), and a nano-BN (50 nm, 0.1 wt%) modified grease (Li + 0.1% nBN). SEM shows that addition nano-BN leads to a more compact soap fiber networks, whereas micro-BN tends to agglomerate and provides limited reinforcement, leaving the base grease with a loose, porous network. Consequently, Li + 0.1% nBN outperforms both Li and Li + 0.1% mBN in dropping point (199.5 °C vs. 194.9 °C and 198.6 °C), oil separation (0.39% vs. 0.64% and 0.44%), and flow point (49% vs. 45% and 47%). Its plateau modulus is significantly higher, reflecting stronger network entanglement. However, Li + 0.1% nBN shows lower structural recovery (61.0%) than Li (65.8%) and Li + 0.1% mBN (67.2%) due to rigid particle–fiber junctions. Notably, Li + 0.1% mBN exhibits a unique frequency-dependent viscoelasticity: higher tanδ at low frequencies but lower tanδ at high frequencies relative to Li. Tribologically, Li + 0.1% nBN reduces friction coefficient by 35% and wear scar diameter by 12.7% compared with Li, outperforming Li + 0.1% mBN. XPS confirms a protective hybrid tribofilm (BN + organic nitrogen species + iron oxides) on the nano-BN lubricated surface. Particle size critically governs BN–fiber interactions and the resulting rheological and tribological performance. Full article

Superhydrophobic materials offer promising prospects for utilization in energy, environmental, and related fields. However, their long-term stability in natural environments is constrained by factors such as mechanical wear and aging, which compromise their practical effectiveness and service life. While notable experimental results have been obtained worldwide, scalable application remains limited by the complexity of the requisite fabrication processes. In this study, a durable superhydrophobic coating was developed through a facile one-step process, utilizing a polyaspartic ester (PAE) matrix reinforced with a composite of self-synthesized fluorinated silica (F-SiO₂) and hexagonal boron nitride (h-BN) micro-/nano-structures. This strategy effectively enhanced filler dispersion within the resin matrix and promoted hydrophobicity, yielding a stable superhydrophobic surface. The resulting coating exhibits significant potential for scalable application. The optimized coating demonstrated a water contact angle of 161.2° and a roll-off angle of 7.6°, showing excellent repellency to water, corrosive liquids, and fluids across a wide pH range, along with remarkable self-cleaning performance. Benefiting from the synergistic enhancement of h-BN and F-SiO₂, the coating also exhibits superior mechanical durability, maintaining a contact angle of 144.4° after 1000 abrasion cycles. Furthermore, in low-temperature anti-icing tests, the coating significantly delayed ice formation on its surface. Notably, after 1000 h of UV aging tests, the F-SiO₂@BN/PAE coating retained its intact superhydrophobic structure, with the water contact angle only slightly decreasing from 159.6° to 152.8°, still within an excellent superhydrophobic state, demonstrating outstanding weather resistance. By integrating surface functionalization with mechanical reliability through a facile one-step fabrication process, this study provides significant insights for the large-scale application of hydrophobic materials in the energy and transportation sectors. Full article

The flooded rice rhizosphere is a continuous reactive interface composed of sediment, porewater, root-surface oxic microdomains, and iron plaque, where redox processes and Fe cycling regulate Cd/As speciation, bioavailability, and plant accumulation. Engineered nanomaterials (ENMs) have shown potential for reducing Cd/As uptake in rice, but the coupled roles of microbial community responses, iron-plaque gating, and cross-interface elemental migration remain insufficiently integrated. This review synthesizes the current evidence on ENM transformation and partitioning at flooded rhizosphere microinterfaces, focusing on front-end speciation changes, root-surface retention, microbial functional regulation, and plant sequestration or transport. Correlative evidence suggests that rhizosphere microorganisms are associated with altered redox conditions, Fe cycling, As methylation potential, and metabolite secretion, which may influence Cd/As partitioning and cross-interface migration. However, direct causal validation of the complete ENM transformation–microbial response–Fe cycling–Cd/As flux–grain accumulation sequence within a single integrated system remains lacking. We further discuss how elevated CO₂, micro-/nanoplastics, Fe/DOM dynamics, and water management regimes may modify this framework, and we identify Sb as a theoretical boundary case because direct ENM–rice evidence remains limited. Finally, we highlight the need to integrate spatial tracing and imaging methods, including persistent luminescence tracing, LA-ICP-MS, NanoSIMS, and µ-XRF/µ-XANES, with metaomics to connect particle localization, microbial function, and contaminant fate. Full article

Friction and wear are major factors affecting the efficiency and reliability of mechanical systems, leading to increasing interest in laser surface texturing (LST) for tribological surface engineering. This review summarizes the development of LST from conventional surface modification to multifunctional interface design and discusses the underlying process–structure–performance relationships. Different lubrication-dependent mechanisms, including micro-hydrodynamic pressure generation, wear debris entrapment, contact stress regulation, metallurgical strengthening, and wettability control, are analyzed under hydrodynamic, boundary, and dry sliding conditions. Representative processing technologies, including nanosecond, ultrafast, direct laser interference patterning (DLIP), and liquid-assisted laser processing, are compared in terms of fabrication precision, thermal effects, scalability, and tribological performance. Recent advances in hybrid surface engineering strategies integrating textures with coatings, solid lubricants, and surface hardening treatments are also reviewed. Representative applications involving bearings, cutting tools, biomedical implants, advanced ceramics, and additively manufactured materials are discussed to summarize application-oriented texture design principles. Current limitations related to thermal damage, manufacturing efficiency, coating stability, and long-term reliability are critically evaluated. Future developments are expected to focus on multifunctional surface integration, large-area manufacturing, and AI-assisted optimization for application-specific tribological interface design. Full article

Ultra-High Molecular Weight Polyethylene (UHMWPE), the standard base material in ski manufacturing, offers excellent gliding performance but exhibits limited mechanical and scratch resistance on hard and icy snow conditions. In this work, stainless steel is proposed as a mechanically robust alternative, and its inherently higher friction against snow is addressed through surface engineering. The snow friction behavior of 301H stainless steel surfaces decorated with fishbone-like microstructures combined with Laser-Induced Periodic Surface Structures (LIPSSs) was investigated using a custom-built snow tribometer. Several pattern designs, with different pitch distances and depths, were engraved using femtosecond laser pulse irradiation. We conducted morphological, physical, and chemical investigations through microscopy, static contact angle measurements, and X-ray Photoelectron Spectroscopy analyses. Results indicate that the gliding performance is not directly related to the modifications in surface chemistry and wetting behavior of the samples but is affected by the geometry and orientation with respect to the sliding direction of the specific micro- and nano-features. Overall, we achieved friction coefficient values comparable to those found in UHMWPE with a fast and economically sustainable single-step laser-texturing process. This approach allows the industrial up-scaling of the fishbone-texture design to real-size alpine ski prototypes. Full article

The growing request for more sustainable materials and environmentally friendly nanofabrication methods in the electronics field has recently driven the scientific community in the development of bio-derived materials as an alternative to conventional lithographic resists. In this work, we used chitosan, a biodegradable and biocompatible polysaccharide, as a green direct-write resist material for Atomic Force Microscopy-based nanolithography. Chitosan thin layers were obtained by spin coating and systematically characterized, in terms of thickness and surface roughness, demonstrating nanoscale smoothness and tunable film thickness. Three Pulse–Atomic Force Lithography (P-AFL) approaches, i.e., Constant Pulse, Gradient Pulse, and Raster Pulse AFL methods, were used to pattern nanostructures with constant-depth nanogrooves, variable-depth (2.5D) profile, and three-dimensional nanoholes on chitosan films. The results reveal high pattern fidelity, reproducibility, and tunability of feature dimensions as a function of applied force and scanning direction. Moreover, the RP-AFL technique enabled the fabrication of well-defined 3D nanostructures with depths matching the film thickness, which is a prerequisite for subsequent pattern transfer. This experimental work provided a first proof-of-concept to adopt chitosan as a more sustainable alternative with respect to conventional resists. Moreover, the results highlight P-AFL methods as a versatile and low-impact nanofabrication strategy, contributing to the development of greener micro- and nano-manufacturing technologies. Full article

To address the issues of pronounced resonance, limited control bandwidth, and insufficient trajectory tracking accuracy in piezoelectric-driven elliptical vibration-assisted cutting (EVC) systems under high-frequency vibration, this paper proposes a trajectory tracking control strategy combining damping control with frequency-domain shaping. First, a damping-control strategy is integrated into the control system to refine the plant’s inherent dynamic properties, suppressing the resonance peak and elevating the system’s stability margin. Second, to enhance the system bandwidth and dynamic response, a high-gain PID controller is designed via frequency shaping. Additionally, given that the nominal model becomes high-order after implementing the damping controller, proportional gain is used for approximate equivalence with the system transfer function, lowering the model order and streamlining controller design. Next, a disturbance observer (DOB) is introduced to estimate and compensate for the unmodeled dynamics in the feedforward path in real time, further improving the trajectory tracking accuracy. Finally, taking the designed piezoelectric-driven EVC device as the controlled plant, the system frequency response is obtained through sweep excitation experiments, based on which the nominal model is identified, and the controller parameters are determined. The experimental results demonstrate that the proposed control strategy effectively suppresses resonance effects, increases system bandwidth, and reduces the trajectory tracking error. In the complex harmonic superposition trajectory tracking experiment, the steady-state tracking error is maintained within ±0.09 μm. These results demonstrate that the proposed approach markedly improves the system’s dynamic response and trajectory tracking performance, thereby providing technical support for high-precision fabrication of micro/nano-structured surfaces. Full article

The non-excavation grouting technology of composite polyurethane materials provides an efficient and economical treatment scheme for deep-seated distresses of asphalt pavements. To quantitatively evaluate the bonding performance between composite polyurethane and cracks in cement-stabilized macadam base, Image J(v1.54p) (National Institutes of Health, Bethesda, MD, USA) image recognition was adopted to analyze the gradation at the interface of cement-stabilized macadam base mixture. The surface free energy theory was applied to quantitatively study the work of adhesion at the interface between three types of nano-modified composite polyurethane materials (G1-2, T-1 (0.1 wt% MWCNTs and 0 NanoSiO₂@KH550), and TG-1 (0.5 wt% MWCNTs and 0.5 wt% NanoSiO₂@KH550)) and cement-stabilized macadam mixture, and predict the interfacial bonding performance. The results showed the bonding performance order as T-1 > G1-2 > TG-1. In addition, the micro-interface between nano-modified composite polyurethane materials and cement-stabilized macadam base was analyzed via SEM images, revealing the bonding mechanism at the interface between them. Full article

Inverse analysis from indentation experiments has been a challenging problem due to the nonlinear relationship between indentation response and material parameters. In this work, a data-driven method is proposed that integrates an artificial neural network (ANN) and evolutionary optimization for the reliable and efficient inverse parameter identification. A large dataset is generated by simulating the indentation process based on different combinations of material parameters in a systematic way. Then, by using the simulated data, a set of ANN models is trained that can efficiently predict the indentation responses, i.e., the displacement–time curve, the indentation force, and the surface profile, as a function of material parameters. These trained models exhibit the potential to replace the computationally expensive numerical simulations for the identification of material parameters by inverse analysis. In this way, the surrogate models make the numerical evaluation of the loss function, which is minimized during the inverse analysis, orders of magnitude faster. This enables the use of the powerful genetic algorithm for the minimization of the loss function, which would be impossible without numerically efficient surrogate models, as this algorithm requires many iterations to produce robust results. In this work, we systematically investigate which mathematical loss function leads to robust and unique results in determining the material parameters through inverse analysis of indentation results. The results show that such an inverse analysis can be successfully performed for simulation data. In forthcoming work, this method will be generalized to experimental indentation data, which will allow the characterization of the mechanical behaviour of materials by micro- or nano-indentation tests. Full article

Although the loading and targeted release of drugs are core biomedical applications of micro-nano robots, they are restricted by the complexity of robot fabrication and drug loading/release regulation. This work adopts magnetic microspheres (MMs) as microrobot bodies, owing to their low driving resistance and ease of preparation, in order to explore the loading and release of anticancer drugs via physical adsorption and chitosan surface functionalization. Two modification routes, chitosan solution (CS) and chitosan colloid (CC), were compared in terms of their efficacy in fabricating magnetic chitosan microspheres (MCMs). The dispersion procedure of chitosan gel (CG)-encapsulated MMs was optimized to obtain microspheres with uniform size and good encapsulation. Doxorubicin (DOX) was used as a model drug, and the optimized microstructure exhibited high loading efficiency and excellent controlled release. This study offers a low-cost strategy to advance micro-nano robots toward targeted drug delivery applications. Full article