•Ni-Ti-O nanopores (NPs) were anodically grown on the NiTi alloy.•The electrolyte to fabricate the NPs is ethylene glycol containing H2O and NaBr.•The NPs show good corrosion resistance and cytocompatibility.In the present work, we report the anodic growth of Ni-Ti-O nanopores (NPs) on NiTi alloy in ethylene glycol (EG) electrolyte containing H2O and NaBr. It is shown that the NPs with diameter concentrated at 50–60 nm can be grown at 10 V in EG electrolyte containing 5 vol% H2O and 0.48 M NaBr. The NP-coated NiTi alloy show lower corrosion current density compared with that of the bare NiTi alloy. In addition, the NPs possess good cytocompatibility and can even promote osteoblast spreading. Good corrosion resistance and cytocompatibility render the Ni-Ti-O NPs promising as coating of the NiTi alloy for biomedical applications.

•Ni-Ti-O nanoporous film (NPF) is fabricated by anodizing NiTi alloy.•The electrolyte to generate the NPF is ethylene glycol containing H2O and NaCl.•Presence of H+ in the electrolyte may accelerate the growth of the NPF.•The conditions for growth of the NPF on NiTi alloy are not proper for pure Ti and Ni.•The NPF of 1.9 μm in thickness exhibit good cytocompatibility.Ni-Ti-O nanoporous film with pore diameters of 60–75 nm are produced anodically on NiTi in ethylene glycol containing 5–10 vol% H2O and 0.15–0.3 M NaCl at 10–20 V. The film fabricated in the NaCl-containing electrolyte are much thinner than those prepared in the HCl-containing electrolyte under similar experimental conditions, implying proper amount of H+ in the electrolyte accelerates formation of the nanopores. Moreover, the experimental conditions to grow Ni-Ti-O nanoporous film on NiTi are not proper for pure Ti and Ni. The film of 1.9 μm in thickness exhibits good cytocompatibility thus is suitable for biomedical applications.

The cultured hepatic cells in vitro are prone to losing their characteristic morphologies and biological functions. To avoid this problem, a hybrid co-culture system was proposed to elucidate the effect of cellular communication on the phenotype of hepatic cells. A monolayer of endothelial cells (ECs) was co-cultured on the surface of a three-dimensional (3D) scaffold embedded with HepG2 cells. In this hybrid co-culture system, the growth of encapsulated hepatic cells is barely influenced by the co-cultured ECs. However, the liver-special functions of hepatic cells, including the albumin secretion and the expression levels of hepatocyte-specific genes, are significantly improved. It is deduced that the improved liver-special functions is likely related to the paracrine mechanisms. Hence, this hybrid co-culture model may open a window for the co-cultivation of the multi-type of cells as well as the study of cell-cell signaling interaction.Open image in new window

•Ni-Ti-O nanopores (NPs) can be fabricated by anodizing NiTi alloy in an ethylene glycol electrolyte containing HCl.•The parameters for growth of the NPs are: voltage 10.0 V; HCl concentration 0.175-0.75 M; H2O content 5.0-11.0 vol%.•Under optimal conditions, Ni-Ti-O NPs 160 μm long can be produced.Although long nanotubes with a large specific surface area are desirable in many applications, it is difficult to produce long Ni-Ti-O nanotubes on nearly equiatomic NiTi alloy in fluoride (F)-containing ethylene glycol (EG) by anodization. In this work, a new electrolyte composed of EG, H2O, and HCl is designed and adopted to fabricate long nanopores rather than nanotubes on the NiTi alloy. By applying an anodization voltage of 10 V to the EG solutions containing 5.0–11.0 vol% H2O and 0.125–0.75 M HCl, Ni-Ti-O nanopores with a diameter of about 70 nm are produced. The nanopore length increases almost linearly with anodization time and by optimizing the experimental conditions, nanopores with a length of 160 μm can be prepared.

In this work, polycrystalline WO3 nanobelts were fabricated via an electrospinning process combined with subsequent air calcination. The resultant products were characterized by X-ray diffraction, field-emission scanning electron microscopy, and high-resolution transmission electron microscopy in regard to the structures. It has been found that the applied voltage during the electrospinning process played the determined role in the formation of the WO3 nanobelts, allowing the controlled growth of the nanobelts. The ultraviolet (UV) photodetector assembled by an individual WO3 nanobelt exhibits a high sensitivity and a precise selectivity to the different wavelength lights, with a very low dark current and typical photo-dark current ratio up to 1000, which was the highest for any WO3 photodectectors ever reported. This work could not only push forward the facile preparation of WO3 nanobelts but also represent, for the first time, the possibility that the polycrystalline WO3 nanobelts could be a promising building block for the highly efficient UV photodetectors.Keywords: electrospinning; nanobelts; photodetector; polycrystalline; WO3;

•Mesoporous leaf-like CuO was scalable synthesized using commercial Cu(OH)2 at room temperature.•The sample has a high surface area of 23.55 m2 g−1 and narrow pore distribution of 3.3 nm.•After 300 cycles, the CuO still kept a capacity of 694.7 mAh g−1 at 500 mAh g−1.Herein, leaf-like CuO with mesoporous structure has been synthesized by treating commercial Cu(OH)2 powder at room temperature for an appropriate time. The BET measurement shows that the obtained CuO has a high surface area of 23.55 m2 g−1 and narrow pore distribution peaking at about 3.3 nm. The electrochemical performances of leaf-like mesoporous CuO are evaluated by cyclic voltammetry and galvanostatic charge-discharge studies. Electrochemical results show that the as-prepared CuO are promising anode materials in LIBs including high specific capacity, good retention and rate property. Even at the high current density of 2000 mA g−1, the mesoporous CuO electrode still can maintain a specific capacity of 490.5 mAh g−1 which is much higher than the theoretical specific capacity of graphite (372 mAh g−1).

•SiC interlayer is synthesized on WC–Co micro-end mills without chemical pretreatment.•Neither the SiC interlayer nor the diamond coating reduces the fracture resistance.•The bi-layer coated tools possess better cutting performance than uncoated tools.•SiC interlayers are a suitable option for adherent diamond coatings on WC–Co tools.In this paper, bi-layer (SiC + diamond) coatings were synthesized on 0.8-mm-diameter cemented carbide micro-end mills. The influences of SiC interlayers and diamond coatings on the morphologies, phase composition and fracture strength were investigated. The cutting performance of the bi-layer (SiC + diamond) coated tools was validated by dry cutting of aluminum alloys. The results indicated that the binder Co reacted with SiC to form cobalt silicides (i.e., Co2Si and CoSi), suggesting that the SiC interlayer suppressed the deleterious effects of Co, successfully. Neither the presence of the SiC interlayer nor the bi-layer coatings reduced the fracture resistance of the tools. The workpieces had a better surface finish after being cut by the coated tools than those cut by the uncoated tools. This result indicated that the bi-layer (SiC + diamond) coated tools exhibited better cutting performance than the uncoated tools. Thus, SiC interlayers were demonstrated as a suitable option for adherent diamond coatings on the cemented carbide components and cutting tools.

•Microstructural evolution of β-SiC films with H2/TMS ratio in Ar-rich plasma•β-SiC faceted nano-sized particles replace granular particles with ratio increase.•Compactness and adhesion increase at ratios below 120:5 and then decrease.Cubic silicon carbide (β-SiC) thin films were synthesized on cemented carbide (WC–Co) substrates as an interlayer for modifying the adhesion of diamond coatings. The influence of varying the hydrogen (H2)/tetramethylsilane (TMS) flow ratios on the microstructure, phase composition and adhesion of the β-SiC films was investigated. It was found that with the increase of the H2/TMS flow ratios, the SiC crystallite size increases from 6.5 nm to 22.2 nm. When the flow ratio was 40:5, the film was formed of loose cauliflower-like agglomerates, containing SiC granular particles. With the flow ratio increased from 40:5 to 120:5, the films became more uniform and denser, resulting in adhesion enhancement. However, when the ratio increased from 160:5 to 200:5, clusters composed of faceted particles replaced the agglomerates, and the adhesion reduced. The β-SiC film deposited with a H2/TMS flow ratio of 120:5 possessed a more uniform and denser structure, as well as better adhesion than the others. After subsequent diamond deposition, homogeneous nanocrystalline diamond coatings were realized on the β-SiC interlayered substrates. Compared with the results on the well-known two-step chemically etched substrates, the diamond coatings deposited on the substrates with the β-SiC interlayer possess excellent adhesion. It was also validated in this research that the β-SiC interlayer deposited with a H2/TMS flow ratio of 120:5 was effective in enhancing the adhesion of diamond coatings prepared on WC–Co substrates.

•Highly ordered Ni–Ti–O nanotubes have been fabricated by one-step anodization.•We find H2O contents in the electrolyte is critical to successful fabrication of the NTs.•The Ni–Ti–O nanotubes are ideal electrode materials for non-enzymatic glucose detection.Anodization is used to fabricate Ni–Ti–O nanotube (NT) electrodes for non-enzymatic glucose detection. The morphology, microstructure and composition of the materials are characterized by field emission scanning electron microscopy (FE-SEM), high resolution transmission electron microscopy (HR-TEM) and X-ray photoelectron spectroscopy (XPS). Our results show amorphous and highly ordered NTs with diameter of 50 nm, length of 800 nm, and Ni/Ti ratio (at %) of 0.35 can be fabricated in ethylene glycol electrolyte supplemented with 0.2 wt.% NH4F and 0.5 vol.% H2O at 30 °C and 25 V for 1 h. Electrochemical experiments indicate that at an applied potential of 0.60 V vs. Ag/AgCl, the electrode exhibits a linear response window for glucose concentrations from 0.002 mM to 0.2 mM with a response time of 10 s, detection limit of 0.13 μM (S/N = 3), and sensitivity of 83 μA mM− 1 cm− 2. The excellent performance of the electrode is attributed to its large specific area and fast electron transfer between the NT walls. The good electrochemical performance of the Ni–Ti–O NTs as well as their simple and low-cost preparation method make the strategy promising in non-enzymatic glucose detection.

•Nanostructured TiO2 films with different concentrations of silver were prepared.•The effects of silver concentrations on microstructure and properties were studied.•The films exhibit excellent antibacterial property and corrosion resistance.•The hardness of the antibacterial TiO2 films is also improved.To prevent bacterial proliferation on biomedical titanium implants, significant efforts have been focused on modifying its surface composition and structure. In this study, nanostructured titania (TiO2) films with different concentrations of silver were prepared by magnetron sputtering and subsequently annealed at 600 °C in air. The effects of silver concentrations on microstructure, antibacterial property, corrosion resistance and hardness were studied. The results indicate that silver contribute to the growth of the TiO2 grains and is uniformly dispersed on the surface of annealed samples. The annealed films with a thickness of about 2.5 μm are uniform and mainly composed of rutile phase and pure titanium. Silver mainly exists in the metallic state in the TiO2 films. The Ag-doped TiO2 films can effectively kill Staphylococcus aureus within 24 h and the antibacterial ability increases with the silver content. The dynamic potential polarization results show that silver incorporation into TiO2 films slightly lower the corrosion potential, but significantly decrease the current density, and the current density decreases as the silver addition increases. Moreover, the hardness of the Ag-doped TiO2 films is also greatly improved.

To achieve precision instrumentation and accurate measurement, there is increasing need for pressure sensors to be well serviced in harsh environments. We report, for the first time, piezoresistance in single-crystalline Si3N4 nanobelts by conductive atomic force microscopy (C-AFM). The transverse electromechanical properties of the Si3N4 nanobelt were investigated under various loading forces applied by the C-AFM tip. The calculated transverse piezoresistance coefficient π[10] of the nanobelt was in the range of 2.2 to 8.8 × 10−11 Pa−1 under the applied loading forces ranging from 25.6 to 135.3 nN. The relationship between the piezoresistance coefficients and the applied forces was almost linear. Significant and linear decreases in nanobelt resistance with increasing loading forces were observed, which exhibited a variation of ∼3 MΩ with a changed force of 1 nN, implying that the pressure sensors have high sensitivity. Stable and repeatable I–V curves through multiple voltage sweepings were accomplished, suggesting that the Si3N4 nanobelts pressure sensors are quite reliable.

Field emission with a low turn-on field and high stability is very important and highly desired for the practical application of nanostructures in electron emitters. In the present study, we report the growth of p-type 3C-SiC nanowires with B dopants and sharp corners created via the catalyst-assisted pyrolysis of a polymeric precursor. The morphologies, structures and field emission (FE) properties of the resultant SiC nanowires were investigated. FE measurements suggest that the B-doped SiC nanowires have excellent FE performance with a low turn-on field of 1.35 V μm−1 and a high field enhancement factor of ∼4895. More importantly, the current emission fluctuation of B-doped nanowires with an applied field of 1.88 V μm−1 at 200 °C could be improved to ∼11% from ∼22% of the undoped counterparts, suggesting that the high-temperature FE stability of SiC nanowires could be significantly enhanced by the B dopants. The excellent FE performances could be attributed to the special p-type triangular prism-like nanostructures with B dopants and numerous sharp corners on the prism edges, which could reduce the effective work function and remarkably increase the emission site density.

•We reported the synthesis of porous TiO2 fibers with high purities.•Current work made the fabrication of porous fibers with tunable structures.•The photocatalytic activities of the fibers with high efficiency were explored.TiO2 semiconductor is one of the important photocatalysts for solar light conversion. The challenge is how to improve their efficiency. Creation of porous structures on/in the fibers could favor them a higher surface area as compared to the conventional solid counterparts, which thus could make the achievement for the desired high efficiency. In present work, we report the fabrication of porous TiO2 fibers with high purity via electrospinning of butyl titanate (TBOT) and polyvinylpyrrolidone (PVP) combined with the subsequent calcination in air. It is found that the TBOT content in the spinning solution plays a profound effect on the growth of the fibers, enabling the synthesis of porous TiO2 fibers with tunable structures and high purity. The photocatalytic activity for hydrogen evolution of the as-fabricated TiO2 nanostrcutres has been investigated, suggesting that porous TiO2 nanomaterials with a high purity and well-defined one-dimensional fiber shape could be an excellent candidate to be utilized as the photocatalyst for hydrogen evolution.

We reported the piezoresistance behaviors of n-type 3C-SiC nanowires, which show that the present SiC nanowires could be an excellent candidate for building robust pressure sensors with high sensitivities.

•Porous Ag-containing TiO2 coatings were prepared by a duplex-treatment.•The duplex-treatment consisted of magnetron sputtering and micro-arc oxidation.•Metal Ag existed as Ag0 state was mainly distributed inside the pores.•The main TiO2 phases that appeared in the coatings were rutile and anatase.•The duplex-treated coatings exhibited excellent antibacterial activity to E.coli.The present work was aimed at developing the antibacterial Ag-containing TiO2 coatings on titanium by combining magnetron sputtering with micro-arc oxidation (MAO). The surface morphology, microstructure, chemical composition and chemical state of the Ag-containing TiO2 layers were characterized using scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The concentration of Ag in the sputtering-deposited AgTi layer on pure titanium was 13.9 wt.%. The MAO coatings were prepared on the AgTi layers under different oxidation duration of 2, 5 and 8 min. The size of the well-separated pores increased by increasing the oxidation duration. Metal Ag existed as Ag0 state was mainly distributed homogeneously inside the pores and the concentrations were 2.36, 2.05 and 1.50 wt.%, respectively. The main TiO2 phases bearing Ca and P species appeared within the structure of the coatings were rutile and anatase. The Ag-containing coating oxidation for 5 min showed excellent antibacterial activity of Escherichia coli (E.coli) within 24 h and the antibacterial rate gradually raised with increasing contact time.

The purity and uniformity issues with tunable structures are significant challenges for the fabrication of porous fibers. In the present work, we reported the fabrication of mesoporous SiC fibers via electrospinning of polyureasilazane and polyvinylpyrrolidone combined with subsequent high-temperature pyrolysis treatment. The resultant mesoporous fibers were systematically characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), and high-resolution transmission electron microscopy (HRTEM). The contents of polyureasilazane within the solutions played a critically important role in the formation of mesoporous SiC fibers, enabling the well-controlled growth of the mesoporous SiC fibers. As compared to the reported works, the as-fabricated mesoporous fibers exhibit very uniform microstructures, very high purities, and highly defined fiber shapes with well-controlled structures, which could inspire and activate their potential applications in photocatalysts and catalyst supports.

Cu modified layer was prepared on the surface of AISI304 stainless steel by plasma surface alloying technique. The effects of processing parameters on the thickness, surface topography, microstructure and chemical composition of Cu modified layer were characterized using glow discharge optical emission spectroscopy (GDOES), scanning electron microscopy (SEM) and X-ray diffraction (XRD). The experimental results show that the surface modified layer is a duplex layer (deposited + diffused layer) with thickness of about 26 μm under the optimum process parameters. The modified layer is mainly composed of a mixture of Cu and expanded austenite phase. The ball-on-disk results show that the modified layer possesses low friction coefficients (0.25) and excellent wear resistance (wear volume 0.005×109 μm3). The Cu modified layer is very effective in killing the bacteria S. aureus. Meanwhile, no viable S. aureus is found after 3 h (100% killed) by contact with the Cu alloyed surface.

Fracture behavior of CrN coatings deposited on the surface of silicon and AISI52100 steel by different energy ion beam assisted magnetron sputtering technique (IBAMS) was studied using indentation and dynamic cycle impact. It is found that, for the coatings on silicon substrate, the cracks form in the indentation corners and then propagate outward under Vickers indentation. The coating prepared using ion assisted energy of 800 eV shows the highest fracture resistance due to its compact structure. Under Rockwell indentation, only finer radial cracks are found in the CrN coating on AISI 52100 steel without ion assisting while in the condition of ion assisting energy of 800 eV, radial, lateral cracks and spalling appear in the vicinity of indentation. The fracture of CrN coatings under dynamic cycle impact is similar to fatigue. The impact fracture resistance of CrN coatings increases with the increase of ion assisting energy.

The Mo surface modified layer on titanium was obtained by the plasma surface alloying technique. The structure and composition of the Mo modified titanium were investigated by X-ray diffraction (XRD) and glow discharge optical emission spectroscopy (GDOES). The Mo modified layer contains Mo coating on subsurface and diffusion layers between the subsurface and substrate. The X- ray diffraction analysis of the Mo modified titanium reveals that the outmost surface of the Mo modified titanium is composed of pure Mo. The electrochemical corrosion performance of the Mo modified titanium in saliva was investigated and compared with that of titanium. The chemical corrosion performance of the Mo modified titanium in 37 °C saliva was investigated and compared with that of titanium. The experimental results indicated that self-corroding electric potentials and corrosion-rate of the Mo modified titanium were higher than that of titanium in saliva. Corrosion-rate of the Mo modified titanium was lower than that of titanium in 37 °C saliva.

The Mo-N surface modified layer on Ti6Al4V alloy was obtained by the plasma surface alloying technique. The structure and composition of the Mo-N modified Ti6Al4V alloy were investigated by X-ray diffraction (XRD) and glow discharge optical emission spectroscopy (GDOES). The Mo-N modified layer contains Mo-N coating on subsurface and diffusion layers between the subsurface and substrate. The X-ray diffraction analysis of the Mo-N modified Ti6Al4V alloy reveals that the outmost surface of the Mo-N modified Ti6Al4V alloy is composed of phase Mo2N (fcc) and Mo2N (tetr). The electrochemical corrosion performance of the Mo-N modified Ti6Al4V alloy in 0.5 mol/L HCl solution was investigated and compared with that of Ti6Al4V alloy. The chemical corrosion performance of the Mo-N modified Ti6Al4V alloy in boiling 37% HCl solution was investigated and compared with that of Ti6Al4V alloy. Results indicate that self-corroding electric potentials and corrosion-rate of the Mo-N modified Ti6Al4V alloy are higher than that of Ti6Al4V alloy in 0.5 mol/L HCl solution. The corrosion-rate of the Mo-N modified Ti6Al4V alloy is lower than that of Ti6Al4V alloy in boiling 37% HCl solution.

Mo and Mo–N surface modified layers were prepared on Ti–6Al–4 V alloy using a double glow plasma surface alloying technique. Impact tests were performed to determine the critical impact load that characterizes the fatigue behavior of the plasma modified Ti–6Al–4 V alloy. Impact tests on nitrided Ti–6Al–4 V alloy specimens were also performed for comparison. Results show that all the three surface modifications have enhanced the surface hardness and load-bearing capacity of the modified Ti–6Al–4 V alloy. Cohesive failure mode was observed on all failed specimens. Amongst the three tested surface modifications, Mo modified Ti–6Al–4 V specimens have the best fatigue strength due to the excellent toughness of their surface modified layers. It seems that surface hardness and toughness of the modified layers should be optimized to ensure a better fatigue strength.

We reported the piezoresistance behaviors of n-type 3C-SiC nanowires, which show that the present SiC nanowires could be an excellent candidate for building robust pressure sensors with high sensitivities.

To achieve precision instrumentation and accurate measurement, there is increasing need for pressure sensors to be well serviced in harsh environments. We report, for the first time, piezoresistance in single-crystalline Si3N4 nanobelts by conductive atomic force microscopy (C-AFM). The transverse electromechanical properties of the Si3N4 nanobelt were investigated under various loading forces applied by the C-AFM tip. The calculated transverse piezoresistance coefficient π[10] of the nanobelt was in the range of 2.2 to 8.8 × 10−11 Pa−1 under the applied loading forces ranging from 25.6 to 135.3 nN. The relationship between the piezoresistance coefficients and the applied forces was almost linear. Significant and linear decreases in nanobelt resistance with increasing loading forces were observed, which exhibited a variation of ∼3 MΩ with a changed force of 1 nN, implying that the pressure sensors have high sensitivity. Stable and repeatable I–V curves through multiple voltage sweepings were accomplished, suggesting that the Si3N4 nanobelts pressure sensors are quite reliable.

Field emission with a low turn-on field and high stability is very important and highly desired for the practical application of nanostructures in electron emitters. In the present study, we report the growth of p-type 3C-SiC nanowires with B dopants and sharp corners created via the catalyst-assisted pyrolysis of a polymeric precursor. The morphologies, structures and field emission (FE) properties of the resultant SiC nanowires were investigated. FE measurements suggest that the B-doped SiC nanowires have excellent FE performance with a low turn-on field of 1.35 V μm−1 and a high field enhancement factor of ∼4895. More importantly, the current emission fluctuation of B-doped nanowires with an applied field of 1.88 V μm−1 at 200 °C could be improved to ∼11% from ∼22% of the undoped counterparts, suggesting that the high-temperature FE stability of SiC nanowires could be significantly enhanced by the B dopants. The excellent FE performances could be attributed to the special p-type triangular prism-like nanostructures with B dopants and numerous sharp corners on the prism edges, which could reduce the effective work function and remarkably increase the emission site density.