Ni Microstructures Research Articles

Screen-printed electrodes decorated with low content Pt–Ni microstructures for sensitive detection of Zn(II), ascorbic acid and paracetamol in pharmaceutical products and human blood samples

In this study, we report for the first time, a method for simultaneous detection of paracetamol (PA) and its toxic impurities, 4-aminophenol (4-AP), as well as commonly co-formulated drugs, ascorbic acid and zinc (AA and Zn(II)), using screen-printed electrodes (SPEs) as a sensing platform. To improve the electrochemical performance of the SPEs, these are decorated with platinum and nickel microstructures (Pt–Ni), using a simple electrodeposition technique. The structures and morphologies of the synthesized Pt–Ni/SPE electrode were confirmed by FE–SEM, TEM, EDX, XRD and AFM measurements. Furthermore, electrochemical characterization of the as-prepared sensor was investigated using cyclic voltammetry and electrochemical impedance spectroscopy methods. Under optimum conditions, the content of 4-AP, PA, AA and Zn(II) was quantified using cyclic voltammetry, differential pulse voltammetry and square-wave voltammetry techniques. The designed sensor exploits a dual effect, leveraging the efficiency of Pt for Zn(II) detection and Pt–Ni for the detection of 4-AP, AA, and PA. On one hand the as-prepared Pt–Ni/SPE sensor exhibits a linear response towards 4-AP and PA, ranging from 0.5 to 200 μM for both, with detection limits of 0.33 µM and 0.23 µM (S/N = 3) for 4-AP and PA, respectively. On the other hand, it demonstrates a linear response towards PA, AA, and Zn(II), ranging from 0.01 to 0.8 μM for Zn(II), 10 to 1800 μM for AA, and 0.5 to 200 μM for PA, with detection limits of 0.004 µM, 9.0 µM, and 0.15 µM for Zn(II), AA, and PA, respectively. Crucially, the as-fabricated sensor, with its remarkable reproducibility, recovery, long-term stability, and anti-interference capabilities, effectively quantified 4-AP, PA, Zn(II) and AA in both pharmaceutical formulations and human plasma samples.

Fabrication of Ni-microstructure through electrochemical deposition using 3D printed solution flow type microdroplet cell

Electrochemical 3D printing of electrical conductors with microscale fabrication grasps large capacities for future industrial applications. Low-cost, and eco-friendly electrochemical additive manufacturing techniques for high-speed printing metals are required. In this work, 3D-printed solution-flow type microdroplet cell (SF-MDC) is proposed as a novel electrochemical deposition technique for fabricating of Ni microstructures on the Cu substrate in localized areas. The influence of current density on the morphology and grain size of Ni electrodeposition was studied. The effect of scanning speed on the deposition thickness was also examined. The surface morphology and crystal structures of the deposited Ni layers were analyzed by scanning electron microscope (SEM) and X-ray diffraction (XRD) techniques. The results showed that as the current density increased, large nodule grain size microstructures with heterogeneous morphology were obtained. The XRD result showed that the deposited Ni crystal was characterized by face-centered cubic (FCC) structure. A thickness of 93.1 µm, 63.5 µm, and 46.3 µm were printed at scanning speeds of 3 µm s−1, 5 µm s−1, and 10 µm s−1, respectively. Free-standing 3D Ni micro-rods were fabricated on a Cu substrate using SF-MDC.

Multi-phase field simulation of Al[formula omitted]Ni[formula omitted] intermetallic growth at liquid Al/solid Ni interface using MD computed interfacial energies

Considering its application in developing Raney-type Ni catalysts and in metal surface coatings, the study on the growth behavior of Al3Ni2 intermetallic compound (IMC) at the Al/Ni material interface is of utmost importance. The present work integrates nanoscale molecular dynamics (MD) calculation with mesoscale phase field model for studying the interfacial phenomena associated with Al3Ni2 growth in Al/Ni interface at 1173.15 K. The interfacial energies computed from MD are in the range 0.9–1.2 J/m2 with FCC/IMC featuring as the interface with the largest value and IMC/LIQUID as the one with the lowest value. Phase field model parameters characterizing a varying interface energy formulation are established to simulate the 2D growth of interfacial IMC grains. With the help of an atomistically informed phase field model, it has been revealed that the phase areas and morphology are obviously sensitive to the interfacial properties. The methodologies and results of these multiscale simulations for IMC interfaced between Al and Ni microstructures offer the complementary and accelerated design route of in-silico studies for materials systems experimented at high temperature.

Laser-Assisted Surface Modification of Ni Microstructures with Au and Pt toward Cell Biocompatibility and High Enzyme-Free Glucose Sensing.

We investigated the influence of morphology of Ni microstructures modified with Au and Pt on their cell biocompatibility and electrocatalytic activity toward non-enzymatic glucose detection. Synthesis and modification were carried out using a simple and inexpensive approach based on the method of laser-induced deposition of metal microstructures from a solution on the surface of various dielectrics. Morphological analysis of the fabricated materials demonstrated that the surface of the Ni electrode has a hierarchical structure with large-scale 10 μm pores and small-scale 10 nm irregularities. In turn, the Ni-Pt surface has large-scale cavities, small-scale pores (1–1.5 μm), and a few tens of nanometer particles opposite to Ni-Au that reveals no obvious hierarchical structure. These observations were supported by impedance spectroscopy confirming the hierarchy of the surface topography of Ni and Ni-Pt structures. We tested the biocompatibility of the fabricated Ni-based electrodes with the HeLa cells. It was shown that the Ni-Au electrode has a much better cell adhesion than Ni-Pt with a more complex morphology. On the contrary, porous Ni and Ni-Pt electrodes with a more developed surface area than that of Ni-Au have better catalytic performance toward enzymeless glucose sensing, revealing greater sensitivity, selectivity, and stability. In this regard, modification of Ni with Pt led to the most prominent results providing rather good glucose detection limits (0.14 and 0.19 μA) and linear ranges (10–300 and 300–1500 μA) as well as the highest sensitivities of 18,570 and 2929 μA mM–1 cm–2. We also proposed some ideas to clarify the observed behavior and explain the influence of morphology of the fabricated electrodes on their electrocatalytic activity and biocompatibility.

Effect of the Microstructures on Vulcanized Rubber Frictions.

Vulcanized rubber is widely used in a wide range of applications because of its flexibility, durability, sealing properties, and high degree of friction. However, this high degree of friction can also become an issue, as it leads to the wearing and breakage of parts. In this report, we investigated the effects of the vulcanized rubber microstructures on friction force by using simple, anisotropic microstructures. The line and space master microstructures were prepared from a photoresist, and the structures were transferred to PDMS, PSt, and then Ni. After surface modification of the Ni microstructures by TEOS, the vulcanized rubber microstructures were fabricated by a simple hot press process with the TEOS-coated Ni microstructure molds. The structural parameters of the vulcanized rubber line and space microstructures were found to be successfully varied by elongation, and the structural deformations were also investigated by FEM simulations. Measurements of the frictional force of the vulcanized rubber microstructures revealed the friction coefficient was reduced by the surface microstructures and was affected by the directions of the contact because of the microstructure anisotropy. The reason for of these results can be explained by the changes in the contact area and hysteresis friction. These results suggest that the friction coefficients of vulcanized rubbers can be reduced by the simple surface microstructures that are applicable to a wide range of fields.

High throughput electrochemically driven metal microprinting with multicapillary droplet cell

A high speed and low-cost electrochemical additive manufacturing method for parallel microprinting of metals is proposed. Multicapillary 3D printed solution flow type microdroplet cells (Sf-MDC) with large capillary diameters (600 μm) are used to electrodeposit high-quality Ni microstructures. Three Ni lines each having a width of around 900 μm and a thickness of around 24.6 μm, 20.7 μm and 15.2 μm are simultaneously printed on Cu substrate. The influence of temperature and scanning speed on the height of printed Ni lines is studied. Independent control of solutions inside each capillary enables the simultaneous formation of Ni-Cu-Ni and Cu-Ni-Cu microdots without any cross-mixing of solutions. By replacing 3D printed inner capillaries (around 600 μm in diameter) with silica capillaries (around 100 μm in diameter) inside the Sf-MDC, free standing 3D structures such as Ni microrods are successfully fabricated. Localized electrodeposition using the Sf-MDC allows parallel process 3D printing of metal microstructures for a wide range of applications.

Facile Synthesis of Bio-Template Tubular MCo2O4 (M = Cr, Mn, Ni) Microstructure and Its Electrochemical Performance in Aqueous Electrolyte

In this project, we present a comparative study of the electrochemical performance for tubular MCo2O4 (M = Cr, Mn, Ni) microstructures prepared using cotton fiber as a bio-template. Crystal structure, surface properties, morphology, and electrochemical properties of MCo2O4 are characterized using X-ray diffraction (XRD), gas adsorption, scanning electron microscopy (SEM), Fourier transforms infrared spectroscopy (FTIR), cyclic voltammetry (CV), and galvanostatic charge-discharge cycling (GCD). The electrochemical performance of the electrode made up of tubular MCo2O4 structures was evaluated in aqueous 3M KOH electrolytes. The as-obtained templated MCo2O4 microstructures inherit the tubular morphology. The large-surface-area of tubular microstructures leads to a noticeable pseudocapacitive property with the excellent electrochemical performance of NiCo2O4 with specific capacitance value exceeding 407.2 F/g at 2 mV/s scan rate. In addition, a Coulombic efficiency ~100%, and excellent cycling stability with 100% capacitance retention for MCo2O4 was noted even after 5000 cycles. These tubular MCo2O4 microstructure display peak power density is exceeding 7000 W/Kg. The superior performance of the tubular MCo2O4 microstructure electrode is attributed to their high surface area, adequate pore volume distribution, and active carbon matrix, which allows effective redox reaction and diffusion of hydrated ions.

Grain-Size-Dependent Grain Boundary Deformation during Yielding in Nanocrystalline Materials Using Atomistic Simulations

While the advantageous mechanical properties of nanocrystalline (NC) materials have stimulated numerous studies over the past decade, fewer studies have looked at the onset of yielding and deformation and the role of grain boundaries (GBs) prior to plastic flow. In this computational study, Ni microstructures with grain size between 6 nm and 20 nm were studied to elucidate the role of GBs during yielding. Residual strain was quantified by relaxing to zero stress during loading and calculating the resulting evolution of strain accommodation. The results of this work reveal the accumulation of plastic strain in GBs and how microplasticity changes with grain size, leading to the initiation of macroscopic yielding. Microplasticity accumulates homogeneously within large grain microstructures, then becomes localized with decreasing grain size. The resulting microstructural strain accommodation helps understand changes in the onset of dislocation plasticity and yielding behavior in NC materials and may have broader implications for their continual plastic deformation.

Controlled synthesis of tubular ferrite MFe2O4 (M = Fe, Co, Ni) microstructures with efficiently electrocatalytic activity for water splitting

Ferrite MFe2O4 (M = Fe, Co, Ni) tubular microstructures were successfully synthesized through a simple two-step strategy. The tubular FeOOH microstructures were first obtained by a heating reflux route. Then, tubular ferrite MFe2O4 (M = Fe, Co, Ni) microstructures were produced by a solvothermal method. The as-prepared products were characterized by the powder X-ray diffraction (XRD), the field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and EDS mapping. Experiments showed that as-obtained ferrite catalysts demanded the overpotentials of −201∼-359 mV or ∼340–432 mV to afford the current density of −/+10 mA cm−2 for hydrogen evolution reaction (HER) or oxygen evolution reaction (OER) with long-term durability for 50 h in 1.0 M KOH solution. Among them, NiFe2O4 tubular microstructures presented the best electrocatalytic activities for HER and OER due to the largest BET specific surface area, the highest electrochemical active surface area and the smallest charge-transfer resistance. Obviously, the present ferrite tubular microstructures have potential application as a bifunctional electrocatalyst for full water splitting.

Cytocompatible magnetostrictive microstructures for nano- and microparticle manipulation on linear strain response piezoelectrics

In this work, we investigate polycrystalline Ni and FeGa magnetostrictive microstructures on pre-poled (011)-cut single crystal [Pb(Mg1/3Nb2/3)O3]1−x-[PbTiO3]x (PMN-PT, x ≈ 0.31) with linear strain profile versus applied electric field. Magnetostrictive microstructure arrays with various geometries are patterned on PMN-PT. Functionalized magnetic beads are trapped by localized stray fields originating from the microstructures. With an applied electric field, the magnetic domains are actuated, inducing the motion of the coupled particles with sub-micrometer precision. This work shows promise of using energy-efficient electric-field-controlled magnetostrictive micro- and nanostructures for manipulating magnetic beads via a linear strain response. The work also demonstrates the viability of cells suspended in solution on these structures when subject to applied electric fields, proving the cytocompatibility of the platform for live cell sorting applications.

Influence of Nonuniform Micron-Scale Strain Distributions on the Electrical Reorientation of Magnetic Microstructures in a Composite Multiferroic Heterostructure

Composite multiferroic systems, consisting of a piezoelectric substrate coupled with a ferromagnetic thin film, are of great interest from a technological point of view because they offer a path toward the development of ultralow power magnetoelectric devices. The key aspect of those systems is the possibility to control magnetization via an electric field, relying on the magneto-elastic coupling at the interface between the piezoelectric and the ferromagnetic components. Accordingly, a direct measurement of both the electrically induced magnetic behavior and of the piezo-strain driving such behavior is crucial for better understanding and further developing these materials systems. In this work, we measure and characterize the micron-scale strain and magnetic response, as a function of an applied electric field, in a composite multiferroic system composed of 1 and 2 μm squares of Ni fabricated on a prepoled [Pb(Mg1/3Nb2/3)O3]0.69-[PbTiO3]0.31 (PMN-PT) single crystal substrate by X-ray microdiffraction and X-ray photoemission electron microscopy, respectively. These two complementary measurements of the same area on the sample indicate the presence of a nonuniform strain which strongly influences the reorientation of the magnetic state within identical Ni microstructures along the surface of the sample. Micromagnetic simulations confirm these experimental observations. This study emphasizes the critical importance of surface and interface engineering on the micron-scale in composite multiferroic structures and introduces a robust method to characterize future devices on these length scales.

An array of leaf-like Co3Ni microstructures with ferromagnetic properties, superhydrophobic properties and high catalytic performance in the hydrolysis of ammonia borane

A Cu foil supported array of leaf-like Co3Ni microstructures simultaneously exhibited ferromagnetic properties, superhydrophobic properties, as well as high catalytic performance in the hydrolysis of ammonia borane.

S0440103 酸化ニッケルナノ粒子のフェムト秒レーザ還元微細パターニング

S0440103 酸化ニッケルナノ粒子のフェムト秒レーザ還元微細パターニング

Modeling and Characterization of MicroPirani Vacuum Gauges Manufactured by a Low-Temperature Film Transfer Process

The novelty of this paper is the proof of functional microdevice fabrication using a recently developed low-temperature transfer process. The process is based on adhesion control of molded Ni microstructures on a donor wafer by using plasma-deposited fluorocarbon films. Low-temperature adhesive bonding of the microstructures on the target wafer using benzocyclobutene sealing enables mechanical tearing off from the donor wafer. Interest of this process for manufacturing microsensors is demonstrated here in the case of microbeams used as pressure sensors based on the Pirani principle. A simple analytical model is used to estimate the electrothermal behavior of the suspended microwires as a function of the ambient gas pressure. Estimations are compared to experimental measurements performed on Ni electroplated microwires of 550-1200-μm length, 10-μm width, and 0.7-7- μm thickness characterized into a vacuum chamber. These microsensors present a maximum of sensitivity in the range of 0.1-100 mbar, which is in line with standard performances of Pirani gauges. The presented results thus demonstrate the interest of a simple film transfer process for the elaboration of 3-D functional microstructures.

MEMS Process by Film Transfer Using a Fluorocarbon Anti-Adhesive Layer

A low cost and low temperature microelectromechanical systems (MEMS) transfer process is presented. The process is based on adhesion control of molded electroplated Ni microstructures on the donor wafer by using a plasma deposited fluorocarbon film. Adhesive bonding of the microstructures on the target wafer using BCB sealing enables mechanical tearing off from the donor wafer. This proposed process has allowed us to realize from 7 μm down to 700 nm thick Ni patterns on Si, Pyrex glass wafers and Kapton foils. Multiple transfers lead to Ni stacked microstructures. We demonstrated the interest of a simple film transfer process for the elaboration of 3D microstructures.

MEMS Process by Film Transfer Using Fluorocarbon Anti-Adhesive Layer

A low cost and low temperature MEMS transfer process is presented. The process is based on adhesion control of molded electroplated Ni microstructures on donor wafer by using plasma deposited fluorocarbon film. Adhesive bonding of the microstructures on the target wafer using BCB sealing enables mechanical tearing out from the donor wafer. This proposed process has allowed us to realize from 7 µm down to 700 nm thick Ni patterns on Si, Pyrex glass wafers and Kapton foils. Multiple transfers lead to Ni stacked microstructures. Because this process is simple and only involves a low temperature (250°C) heating of the host wafer, it is highly versatile and suitable for various applications and brings new perspectives towards 3D integration of MEMS/NEMS.

Topological characteristics of plane sections of polycrystals

Homology metrics have been used to assess the connectivity of grain boundary networks in plane sections of polycrystals. The analysis is based on orientation maps, and four characteristic microstructure types were examined: SrTiO 3 microstructures with normal and bimodal grain size distributions and two Ni microstructures with different concentrations of Σ3 grain boundaries. The inverse connectivity, defined as the ratio of the number of independent pieces of the network to the number of closed loops, is proposed as a metric for the extent to which certain types of grain boundaries are connected. The variation in inverse connectivity with disorientation threshold, below which boundaries are excluded from the network, produces distinct signatures for the different microstructures.

Micro Pirani vacuum gauges manufactured by a film transfer process

A low cost and low temperature transfer process of electroplated Ni microstructures is presented. The process is based on adhesion control of molded Ni microstructures on donor wafer by using plasma deposited fluorocarbon film. Low temperature adhesive bonding of the microstructures on the target wafer using BCB sealing enables mechanical tear out from the donor wafer. Interest of this process is demonstrated here in the case of micro pressure sensors based on the Pirani principle. Suspended Ni electroplated microwires of 0.55 to 1.2 length, 10 μm width and 700 nm to 10 μm thickness were characterized into pressure dependant chamber. These sensors exhibit good sensitivity in the range of 0.1 to 100 mbar. The presented results thus demonstrate the interest of a simple film transfer process for elaboration of 3D microstructures.

Synthesis and Growth Mechanism of Ni Nanotubes and Nanowires

Highly ordered Ni nanotube and nanowire arrays were fabricated via electrodeposition. The Ni microstructures and the process of the formation were investigated using conventional and high-resolution transmission electron microscope. Herein, we demonstrated the systematic fabrication of Ni nanotube and nanowire arrays and proposed an original growth mechanism. With the different deposition time, nanotubes or nanowires can be obtained. Tubular nanostructures can be obtained at short time, while nanowires take longer time to form. This formation mechanism is applicable to design and synthesize other metal nanostructures and even compound nanostuctures via template-based electrodeposition.

Electroplating using high-aspect-ratio microstructures fabricated by proton beam writing

Proton beam writing (PBW) is one of the direct write techniques for the purpose of deep micromachining. Together with the flexibility of the direct write feature, micromachining of high-aspect-ratio structures is possible due to the straight trajectory of the MeV energy protons. However, direct writing is a low throughput process, when compared with a mask process such as UV lithography. For better productivity, coupled use of PBW with electroplating has been proposed as a method to fabricate metal microstructures for molds of imprint lithography. We demonstrate the electroplating of high-aspect-ratio Ni microstructures on PMMA micromachined by PBW.