Metal Substrate Research Articles

Plasma surface modification has emerged as a powerful, versatile tool for tailoring the surface properties of biomedical devices and implants without altering the material characteristics in the bulk. This comprehensive review critically examines the current state-of-the-art in plasma-based surface engineering techniques, with a focus on enhancing biocompatibility, bio-functionality, and long-term performance of medical implants. The article systematically explores various plasma processes and their roles in modifying surface chemistry, topography, energy, and wettability. These alterations directly influence protein adsorption, cell adhesion, antibacterial activity, and corrosion resistance, all of which are crucial for successful clinical integration. Special emphasis is placed on the plasma treatment of metallic (e.g., titanium, stainless steel), polymeric (e.g., polytetrafluoroethylene, polyetheretherketone), and composite substrates commonly used in dental, orthopedic, and cardiovascular applications. This review also highlights synergistic strategies, such as plasma-assisted grafting of bioactive molecules and nanostructuring, that enable multifunctional surfaces capable of promoting osseointegration, mitigating inflammation, and preventing biofilm formation. Emerging trends such as atmospheric cold plasmas and the integration of plasma technology with additive manufacturing are outlined as promising future directions. By synthesizing insights from surface science, materials engineering, and biomedical research, this review provides a foundational framework to guide future innovations in plasma-treated biomaterials. It aims to inform both academic researchers and medical device developers seeking to optimize implant–tissue interactions and achieve improved clinical outcomes.

Abstract Randomly oriented hexagonal zinc (Zn) electrodeposits severely compromise the stability and reversibility of Zn‐metal electrodes. These deposits originate from localized interfacial high current densities and the preferential growth of (002) planes extending into the electrolyte. The electroconvection in the bulk electrolyte can amplify interfacial ion depletion and further exacerbate the uneven interfacial electrochemical reactions. Here, it is demonstrated that benzyl alcohol acts as a blocking agent on the metal substrate, enabling synchronized charge transfer across the electrode‐electrolyte interface. This synchronized charge transfer process facilitates the incorporation of newly formed Zn atoms into step edges of the substrate lattice via a screw dislocation growth mechanism. Such a strategy promotes effective layer‐by‐layer growth, yielding uniform and compact Zn deposits. As a result, Zn||Zn cells exhibit exceptional plating/stripping stability for over 2800 h and maintain resilience at an 80% depth of discharge of Zn (DOD Zn ). Under a limited Zn supply (50% DOD Zn ), Zn||Ti cells achieve an average Coulombic efficiency of 92.8%, highlighting the high reversibility of Zn‐metal electrodes. Additionally, Zn||VS 2 full cells with a 10 µm‐thin Zn‐metal foil show significantly enhanced electrochemical reversibility and capacity retention. This work establishes a universal framework for stabilizing metal electrodes, prioritizing electrodeposition step synchronization over isolated process optimization.

Abstract Molecular assemblies based on porphyrins (Pors), specifically Por nanotapes (NTs) containing magnetic metal ions, offer a versatile platform to explore magnetic interactions arising from the electronic interplay between ‐conjugated ligands and transition metal d ‐orbitals. Using on‐surface synthesis under ultra‐high vacuum, we synthesized ‐extended PorNTs of different lengths incorporating magnetic metal ions such as Fe and Co on Au(111). We resolved their atomic structure using scanning tunneling microscopy (STM) and non‐contact atomic force microscopy (nc‐AFM). Differential conductance () measurements, interpreted by extensive density functional theory calculations and theoretical modeling, reveal two distinct magnetic behaviors for the Fe‐ and Co‐based systems. In FePorNTs, the magnetic interactions are dominated by strong Fe–ligand ferromagnetic coupling and weak antiferromagnetic Fe–Fe coupling. By contrast, CoPorNTs exhibit stronger Co–Co antiferromagnetic exchange and weaker Co–ligand coupling, with Kondo screening evident at the ligand sites. Our findings underscore the profound influence of metal centers, ligands, and substrate interactions on the magnetic and electronic properties of PorNTs, establishing these assemblies as interesting building blocks for low‐dimensional magnetism and future spintronic or quantum‐material applications.

Molecular assemblies based on porphyrins (Pors), specifically Por nanotapes (NTs) containing magnetic metal ions, offer a versatile platform to explore magnetic interactions arising from the electronic interplay between -conjugated ligands and transition metal d-orbitals. Using on-surface synthesis under ultra-high vacuum, we synthesized -extended PorNTs of different lengths incorporating magnetic metal ions such as Fe and Co on Au(111). We resolved their atomic structure using scanning tunneling microscopy (STM) and non-contact atomic force microscopy (nc-AFM). Differential conductance ( ) measurements, interpreted by extensive density functional theory calculations and theoretical modeling, reveal two distinct magnetic behaviors for the Fe- and Co-based systems. In FePorNTs, the magnetic interactions are dominated by strong Fe-ligand ferromagnetic coupling and weak antiferromagnetic Fe-Fe coupling. By contrast, CoPorNTs exhibit stronger Co-Co antiferromagnetic exchange and weaker Co-ligand coupling, with Kondo screening evident at the ligand sites. Our findings underscore the profound influence of metal centers, ligands, and substrate interactions on the magnetic and electronic properties of PorNTs, establishing these assemblies as interesting building blocks for low-dimensional magnetism and future spintronic or quantum-materialapplications.

The mechanical properties of anodic oxide films of Nb, Ta and Zr were studied by the nanoindentation method. Anomalously high elastic recovery after deformation was observed for oxides with thickness of 20 nm. An analogue of this behavior can be elastic membrane fixed on soft base that does not prevent the membrane from bending. Increase of the oxide thickness to 300 nm reduced the effect associated with the high elasticity of oxide and easy deformation of the soft metal substrate, and was accompanied by an increase in the plastic component of deformation, which is similar to the behavior of ceramic materials with low elastic and significant residual plastic deformation.

Saturated heterocycles are privileged pharmacophores, yet their synthetic development is often limited by a narrow substrate scope and metal dependence. We describe a metal-free photochemical strategy catalyzed by a persistent radical cation (PTH•+) that facilitates cycloisomerization via oxidative radical-polar crossover (ORPC). This approach converts CF3•-derived alkyl radicals into alkylsulfonium intermediates as masked carbocations, enabling efficient synthesis of CF3-functionalized γ-butyrolactones and tetrahydrofurans in 25-85% yields. The reaction features broad substrate compatibility, including challenging radicals, and proves to be effective in late-stage modification of bioactive molecules, highlighting its potential for complex heterocycle synthesis.

As they are liquids at room temperature, gallium-based metal substrates allow catalytic metal atoms to move freely without lattice constraints, thereby facilitating the development of catalysts with reconfigurable structures. Here we design an iron-embedded liquid metal catalyst that enables reversible switching of the aggregation and electron spin of iron atoms by controlling an external magnetic field. This facilitates a reversible conversion of the primary liquid products, methyl hydroperoxide (CH3OOH) and acetic acid (CH3COOH), under ambient conditions. The catalyst achieves promising production rates (CH3OOH, 1,679.6 ; CH3COOH, 790.5 ) and high selectivities (CH3OOH, 99.9%; CH3COOH, 91.7%). In the absence of the magnetic field, iron atoms are atomically dispersed, leading to the C1 pathway without C-C bond coupling. When a magnetic field is applied, iron atoms cluster, favouring CH3COOH production in the C2 pathway. The product distribution can be finely and reversibly tuned with magnetic field intensity adjustments ranging from 0 to 500 G. Our findings highlight the potential for using an external magnetic field to precisely control catalytic pathways.

Soft robots manufactured from compliant materials are highly versatile and can interact safely with humans while performing complex tasks. However, their low modulus and high compliance make them vulnerable to mechanical damage. Here, we synthesise soft, self-healing, and recyclable robots featuring complex air chambers using 3D digital light printing technology. The formulated monomers and cross-linkers are polymerized layer-by-layer using photoinitiated free-radical polymerization during the printing process to form soft objects on a moving metal substrate. Dynamic chemistry is introduced into the polymer by designing cross-linker structures, whereby vinylogous urethanes-bearing cross-linkers of different chain lengths are studied to allow the cross-linked elastomer networks to be thermally triggerable for self-healing and reprocessing. The resultant elastomer exhibits a tensile strength of 3.51 ± 0.1MPa and an elongation at break of 454 ± 56% with optimized formulations and printing parameters. The printed soft grippers and crawlers are investigated for their static and dynamic performance after being punctured, cut in half, and left to self-heal at room temperature for 24h. They exhibit excellent self-healing capabilities with efficiencies of 94.5% and 87.5%, respectively. This new approach creates self-healing, recyclable soft robots with complex geometries through additive manufacturing, enabling sustainable, resilient robots for challenging environments.

Using the pulsed laser deposition method, we investigated the fabrication and properties of β-Ga2O3 nanowires on sapphire substrates with various metal catalysts. Although most previous research has focused on growing Ga2O3 nanowires using Au and Ag catalysts, there has been limited investigation into other metal catalysts. Under the growth conditions employed in this study, β-Ga2O3 nanowires were successfully grown on sapphire substrates using Au, Ag, Cu, Ni, and Ti catalysts. The morphology and growth rates of the nanowires varied significantly depending on the type of metal catalyst and substrate. For Au, Ag, and Cu catalysts, the primary growth mechanism of the β-Ga2O3 nanowires was identified as the vapor–liquid–solid process, whereas for Ni and Ti catalysts, growth was predominantly governed by the vapor–solid mechanism. In contrast, under identical growth conditions, metals such as Sn and Cr failed to act as effective catalysts for nanowire growth due to their inability to sustain catalytic activity at the given temperature. Furthermore, the optical properties of the β-Ga2O3 nanowires were found to vary with the type of catalyst used. This study elucidates the correlation between the feasibility of nanowire growth, the resulting nanowire characteristics, and the properties of the metal catalysts, such as their melting points and eutectic points with Ga, through analysis of the phase diagram.

An integrated logistics wireless monitoring system via laser-induced selective metallization and polymer-based substrate engineering strategy

In response to the difficulty of adsorbing 3,4-Benzo(a)pyrene (3,4-Bap) molecules onto the surface of precious metal substrates due to their hydrophobicity, a surface-enhanced Raman scattering (SERS) substrate (SD@AuNPs substrate) was constructed with the dual function of adsorption–detection. The substrate is a gold nanoparticle modified by sulfhydryl cyclodextrin, and the hollow cylindrical structure of cyclodextrin lends hydrophobicity to capture the molecule, which is utilized to achieve on-site selective analysis of 3,4-Bap pollutants using the signal changes in SERS spectra. The theoretical simulations and experimental results presented in this paper show that the maximum value of the electromagnetic enhancement property |E/E0| of the substrate reaches 161. Under the synergistic ‘electromagnetic-chemical’ dual enhancement mechanism, the enhancement factor value of the substrate (EFt = 4.87 × 109) was comparable in order of magnitude to the experimental value (EFe = 1.99 × 108). The construction of the SD@AuNPs substrate and its mechanism study provide a theoretical and practical basis for SERS sensing of 3,4-Bap molecules in complex systems.

Precise manipulation of individual molecules to construct artificial superstructures presents a powerful strategy for investigating novel quantum phenomena. Despite this potential, vertical manipulation within densely packed C60 arrays remains challenging. Here, we demonstrate the successful vertical manipulation of individual C60 molecules within a well-ordered 4 × 4 phase C60 monolayer array on Cu(111) surfaces using a scanning tunneling microscope. This minimally invasive and highly precise technique enables site-specific removal and placement of molecules without perturbing the surrounding structure, thereby allowing for the creation of well-defined vacancy patterns. Using this method, we constructed an artificial C60 honeycomb lattice that maintains structural stability at 78 K. This method provides a reliable strategy for fabricating site-specific defects and customized molecular patterns within C60 arrays, offering an efficient platform for investigating the novel properties of artificial C60 lattices assembled on metal substrates.

Abstract The need for efficient and sustainable energy storage has driven the development of hybrid supercapacitors (HSCs). These devices combine capacitive and battery-type electrodes to deliver high energy and power densities. Designing advanced battery-type electrode materials is crucial for meeting industrial requirements for next-generation devices. Bimetallic spinel cobaltites (MCo 2 O 4 ; M = Mn, Fe, Ni, Cu, Zn, and Mg) are promising options. They provide high theoretical capacity, multiple redox-active sites, and robust structural stability. Recent studies have focused on various strategies to enhance performance. These include elemental doping, controlling morphology, direct growth on conductive substrates, and forming binary or ternary composites with carbon materials, metal oxides or sulfides, layered double hydroxides, conducting polymers, and emerging two-dimensional (2D) or framework materials. Understanding how structure influences performance is key to optimizing charge storage and electron transport. This review highlights progress in designing spinel cobaltite-based battery-type materials for HSCs, with an emphasis on strategies that boost electrochemical performance. It specifically highlights studies reporting on the specific capacity (C g⁻ 1 or mAh g⁻ 1 ), as this metric directly reflects the practical application of these materials in energy storage devices. The review also discusses the main challenges and future research directions for industrial translation and scalable development of advanced battery-type electrodes for high-performance HSCs. Graphical abstract Advances in performance-enhancement strategies for bimetallic spinel cobaltites (MCo 2 O 4 , M = Mn, Fe, Ni, Cu, Zn, Mg) as battery-type electrodes in hybrid supercapacitors. The diagram highlights key approaches, including morphology engineering, elemental doping, conductive substrate integration, carbon-based composites, metal oxide/sulfide and ternary composites, conducting polymer composites, and advanced 2D/framework materials, emphasizing the structure–property–performance relationship for optimized electrochemical behavior.

Abstract Advancements in utilizing low refractive index dielectric particles have implications for sensing, lasing, and strong‐coupling at nano and microscopic scales. These cavities offer benefits like ease of fabrication and biocompatibility, making them promising for a wide range of technologies by utilizing their narrow linewidth modes. However, optical modes sustained in these dispersive systems can show distinct behaviors depending on the detection configuration. This study shows the influence of numerical aperture (NA) of the objective lens on the detection of Mie modes in a dielectric microsphere under far‐field excitation and collection. It is demonstrated experimentally and numerically that Mie modes from microspheres outcouple at different angles, with variations in mode amplitudes contingent on the NA of the objective lens, thus leading to distinct linewidths while probing with different NA objectives. Furthermore, it is shown that metallic substrates can facilitate efficient detection of Mie modes by redirecting scattered modes towards low angles. This enables mode detection with low NA lenses and further preventing the inclusion of incident scattered light from higher angles which otherwise perturb the modes. The results underline the importance of careful detection strategies to fully harness dielectric particles as optical platforms for applications in particle detection and characterization.

Abstract Single‐atom catalysts (SACs) with atomically dispersed metal centers exhibit unparalleled atomic utilization efficiency in Fenton‐like Avenue. However, current strategies lack precise control over the introduction of active dopants to tailor the coordination environment (CE) of active sites, significantly restricting catalytic performance. Herein, to overcome the limited intrinsic activity of M‐N 4 ‐configured of SACs with symmetrically distributed charge on metal sites, “electron‐rich phosphorus (P)‐doping strategy” is conducted to modulate the second‐shell CE of Ni active center (Ni‐NCP 2 ), achieving ultra‐high Fenton‐like performance (over 98% tetracycline removal efficiency within 10 min). The phosphorus dopants, acting as nonmetallic coordination sites, not only enhance pollutant adsorption but also serve as PMS activation accelerators, circumventing the requirement for interfacial electron transfer between the catalyst and PMS. In situ characterizations and Density functional theory (DFT) calculations elucidates two key enhancement mechanisms: i) significantly improved PMS adsorption (adsorption energy: −3.42 eV of Ni‐N 4 P versus −1.89 eV of Ni‐N 4 ), and ii) reduced energy barriers for * O intermediates dimerization into adsorbed 1 O 2 (0.32 eV of Ni‐N 4 P versus 0.91 eV of Ni‐N 4 ). This work establishes an atomic‐level coordination engineering framework for SACs, enabling superior Fenton‐like activity with selective non‐radical pathway dominance, thereby advancing rational design principles for next‐generation environmental catalysts.

We present a simple and efficient process for fabricating III-Nitride (III-N) mechanical resonators on flexible metal substrates. This method combines Van der Waals epitaxy of III-N epilayers with the deposition of a thick metal stressor atop the III-N layers. During thermal treatment, the 30 μm thick metal stressor deposited on a 300 nm AlGaN/500 nm GaN layer grown on a 3 nm two-dimensional hexagonal-Boron Nitride (2D h-BN) release layer, initiates a one-step Self-Lift-Off and Transfer (SLOT) process. This process effectively transfers the III-N heterostructure from the h-BN/Sapphire growth wafer to the flexible metal stressor substrate. Additional local etching of the metal stressor and deposition of front electrodes allow for releasing self-standing III-N layers with integrated actuation. Fabricated III-N MEMS drum resonators were analyzed using optical profilometry and laser Doppler vibrometer, enabling the observation of static deflections and distinct vibration modes. Finite element method (FEM) simulations were also performed to further understand experimental observations and assess the mechanical properties of the released III-N layers, particularly enabling the estimation of stress in the GaN and AlGaN released layers. This straightforward approach not only provides a practical solution for cost-effective III-N MEMS resonators but also ensures flexibility, and crack-free structures.

Abstract The synthesis of mesoporous carbon thin films is proposed on titanium plates with well‐ordered 70 nm mesopores via soft templating of resol resins with poly(ethylene oxide)‐block‐poly(hexyl acrylate) copolymers. Surprisingly, regular carbonization in pure argon suffers from a metal substrate corrosion not yet observed in literature. This corrosion phenomenon is investigated by secondary ion mass spectrometry, electron microscopy, and X‐ray diffraction, and it is identified that the introduction of carbon monoxide into the carbonization atmosphere as successful approach to suppress substrate corrosion without changing microstructure, composition, or pore structure of the non‐graphitic carbon. The model electrodes, which consist of a 200–300 nm thick mesoporous carbon layer, the titanium substrate, and a 200 nm thick titanium carbide interphase, are tested for their suitability as electrocatalyst support: The electric transport through and along the thin film is investigated by impedance and Hall measurements and contrasted to similarly mesoporous IrO2 thin films. Accessibility of the pore system and electrochemical stability under acidic water‐splitting conditions are studied by SIMS and cyclovoltammetry, respectively. The mesoporous carbon thin films reveal a conductivity similar to IrO2, high stability, and (tunable) accessibility, rendering them a promising model system for several applications like electrocatalysis and sodium‐ion batteries.

Surface organic coatings (SOCs) composed of drying oils, resins, and bitumen were commonly applied to small Renaissance bronze sculptures to enhance their visual and physical properties, producing dark, lustrous surfaces that were both esthetic and protective. Yet, the identification of these coatings remains challenging due to aging, conservation interventions, and the damage caused by physical sampling. This study presents a reproducible, non-destructive protocol for characterizing SOCs on metal substrates using external reflection Fourier transform infrared spectroscopy (ER-FTIR) and fiber optic reflectance spectroscopy (FORS). Twenty-seven reference coating mock-ups of linseed oil, walnut oil, mastic resin, pine resin, and bitumen were stoved onto bronze coupons and artificially aged. Spectra were analyzed across the visible/near-infrared (VIS-NIR) (~400–1000 nm), short-wave-infrared (SWIR) (~1000–2500 nm), and mid-infrared (MIR) (~2.5–25 µm) ranges, with key diagnostic features identified for each component and blend, including primary absorptions, combination bands, and overtones. ER-FTIR proved highly effective in detecting oil–resin mixtures and later wax coatings through characteristic bands in the MIR, while FORS, enhanced by first-derivative processing, successfully differentiated triterpenoid and diterpenoid resins and identified multi-component SOCs in the SWIR region. The reference spectral database generated in this study is intended to serve as a comparative tool for future non-invasive analysis of organic coatings on metal surfaces and to demonstrate that ER-FTIR and FORS, used in tandem, offer a practical and scalable framework for the non-destructive identification of SOCs.

Benzoheterocycle polyimides (PIs) demonstrate exceptional metal substrate adhesion, positioning them as high-performance alternatives to conventional heterogeneous adhesives. These materials significantly enhance the weather resistance of flexible batteries and facilitate the development of thinner and lighter PI-based aluminum-plastic flexible packaging. Through molecular engineering of benzoheterocycle PI backbones, a series of ternary copolyimides (BIBOPIs) were synthesized utilizing four structurally distinct flexible diamine monomers. The thermodynamic properties, solvent resistance, water absorption, and coating adhesion of BIBOPIs were systematically evaluated. The distinctive molecular architectures of flexible diamines impart unique physicochemical properties to BIBOPIs. The light transmittance of BIBOPIs incorporating 4,4′-diaminodiphenylsulfone (DDS) exceeds 73%, with BIBOPI-0.5DDS achieving a transmittance of 85% at a wavelength of 800 nm. The light transmittance of BIBOPI-0.5RODA is reduced compared to that of BIBOPI-0.3RODA as the content of flexible ether groups in the molecular chain increases, consequently limiting its visible light transmittance. With the incorporation of a third monomer, the glass transition temperature (Tg) values of BIBOPIs demonstrate a consistent decrease, ranging from 332 to 410 °C. With the increase in 1,4-bis(4-aminophenoxy)benzene (RODA) ratio, the elongation at break of BIBOPIs exhibits a significant rise, from 6.8% for BIBOPI-0.1RODA to 33.8% for BIBOPI-0.5RODA. BIBOPIs demonstrate exceptional solvent resistance at both ambient and elevated temperatures. Additionally, the water absorption (WA) of BIBOPIs decreases as the proportion of the third component increases. The adhesion grade of BIBOPI coatings is 0, with the exception of BIBOPI-0.1DDS, BIBOPI-0.1BPDA, and BIBOPI-0.1ODA. Pull-off experiments demonstrate that the incorporation of a flexible third monomer enhances the adhesion between BIBOPI coatings and substrates, with the adhesion strength surpassing 21.7 MPa. Unlike previous studies, the PI coating developed in this research enables the formation of a metal substrate protective layer with excellent adhesion, achieved through molecular design and structural optimization, without requiring complex surface treatment techniques. The optimized coating architecture enables molecular-level integration with dense PI protective layers, providing critical insights for developing advanced benzoheterocycle PI-based aluminum-plastic flexible packaging systems.

Here, we present a theoretical study on the electric field intensity (EFI) and magnetic field intensity (MFI) distributions outside a single dielectric microsphere placed on a metal substrate. For the first time, intense unconventional optical standing wave patterns (UOSWPs) are observed outside the metal substrate-supported microsphere at the resonant wavelengths or wavelengths of whispering gallery modes (WGMs). However, the conventional and reflective photonic nanojets (PNJs) are observed at the non-resonant wavelengths. The minimum separation between the UOSWPs and the microsphere’s surface is found to be sensitive to the microsphere’s radius (r). The EFI and MFI distributions are analyzed across different planes for transverse electric (TE) and transverse magnetic (TM) polarized light to characterize the UOSWPs. Finally, a comparison is made between UOSWPs observed outside a metal-supported microsphere and conventional optical standing wave patterns (COSWPs) or WGMs observed at the interface of a substrate-free dielectric microsphere. In the case of the substrate-free dielectric microsphere, most of the electric and magnetic fields of WGMs exist inside the microsphere, and only the weak field or evanescent of the WGMs is accessible outside the microsphere for practical applications. In contrast to the WGMs, the intense electric and magnetic fields of the UOSWPs exist outside the microsphere and can enhance the light-matter interaction significantly. Hence, we strongly believe that the UOSWPs will have several potential applications in various research domains.Supplementary InformationThe online version contains supplementary material available at 10.1038/s41598-025-13142-9.