钛氧膜生物相容性与生物活性的研究与应用

对钛氧膜的生物相容性和生物活性的研究及应用进行了评述。重点讨论了钛氧膜的制备方法、钛氧膜的活化处理方式以及钛氧膜在心血管材料和骨替代材料中的应用前景。

多聚赖氨酸修饰钛氧膜并固定纤连蛋白对内皮细胞生长的影响

为了进一步提高钛氧膜与内皮细胞的亲和性,研究了一种表面生物化学方法对钛氧膜表面内皮细胞生长的影响。先利用盐酸和双氧水活化钛氧膜表面,使其产生羟基基团,再涂覆多聚赖氨酸作为中间过渡层,最后在表面上固定纤连蛋白。采用傅立叶红外光谱仪、X射线光电子能谱仪及接触角测量的方法对每步处理后的材料表面进行分析与测试。通过体外人脐静脉原代内皮细胞培养实验评价内皮细胞在样品表面的黏附和生长。研究结果显示,通过表面活化后涂覆多聚赖氨酸并固定纤连蛋白的方法能促进内皮细胞在钛氧膜表面的黏附和生长。

钛氧膜表面原位构建树状分子的仿生性能研究

为提高钛氧膜表面官能团密度,改善其血液相容性,特在其表面原位构建多羟基树状分子。本文通过合成11-羟基十一烷基膦酸(HUPA)后在钛氧膜表面进行自组装,通过依次重复利用传统的亲核取代反应等,制备三代端羟基树状表面。选用红外(FTIR)对HUPA的合成进行定性表征,利用扫描电子显微镜(SEM)进一步观察材料表面形貌并检测制备于氧化钛薄膜端羟基树状表面润湿性的改变,通过血小板粘附实验考量改性后钛氧膜的抗血小板粘附与激活的能力。采用纤维蛋白原粘附实验进一步测试改性材料的血液相容性。实验结果表明端羟基树状表面的制备有效改善了氧化钛薄膜的抗凝血性能,同时提高了材料表面的官能团数量,为后续的组装改性提供了条件。

用等离子体方法以及化学处理对Ti-O薄膜进行活化改性的研究

采用磁控溅射法制备Ti-O薄膜，然后采用等离子体浸没离子注入设备，以氢气作为离子注入源，轰击至钛氧薄膜表面，使其产生羟基基团。并对注入后样品进行酸活化，以期得到更多的羟基。采用傅立叶红外光谱仪（FTIR）、X射线衍射（XRD）、X射线光电子能谱仪（XPS）、扫描电子显微镜（SEM）等对材料表面的结构、成份、官能团变化进行表征。研究结果显示，Ti-O薄膜经H^＋注入后再进行活化，磁控溅射Ti-O薄膜得到明显增多的羟基。

Fabrication of titanium oxide films at low temperature from aqueous solution

Titanium oxide thin films were prepared on self-assembled monolayers-coated silicon substrate using layer-by-layer self-assembly method and chemical bath deposition from an aqueous solution. The effects of temperature on structural properties, thickness and morphologies of titanium oxide thin films were investigated. The results show that the absorption peak of peroxo complexes of titanium at 410 nm decreases gradually with increasing the temperature. The deposited films consisting of titanium oxide nanocrystals are believed to be fully amorphous by XRD. Titanium oxide thin films fabricated at 60 °C for 2 h are continuous, dense and homogeneous with a size in the range of 20-40 nm by SEM. The chemical compositions of deposited thin films were studied by EDS, and the mole ratio of O to Ti is 2.2：1.

Preparation, formation mechanism and mechanical properties of multilayered TiO_2-organic nanocomposite film

Ti O2-organic multilayered nanocomposite films were deposited on a self-assembled monolayer-coated silicon substrate based on layer-by-layer technique and chemical bath deposition method by a hydrolysis of Ti Cl4 in an acid aqueous solution. The chemical compositions, surface morphologies and mechanical properties of the films were investigated by X-ray photoelectron spectrometer(XPS), scanning electron microscopy(SEM) and nanoindentation depth-sensing technique, respectively. The results indicate that the major chemical compositions of the films are Ti and O. The principal mechanism for the nucleation and growth of the films is homogeneous nucleation, and the layer number of films has great influence on the surface morphology and roughness of the films. In addition, mechanical nanoindentation testing presents a significant increase in hardness and fracture toughness of titanium dioxide multilayered films compared with single-layer titanium dioxide thin film.

Structure, Electrical and Oxygen Transport Properties of Fe-Doped SrCoO3-δ Perovskites

The structure-property relationship of Fe-doped SrCoO3-δ was studied. With increase of Fe content in SrCol-xFexO3-δ from x=0 to x=0.2, the phase composition changed pro- gressively in the order of hexagonal→brownmillerite （main）＋hexagonal→cubic （main）＋ brownmillerite→single cubic phase. Transition between the hexagonal/brownmillerite phase and the cubic phase took place with variation of the operating conditions, and was associated with remarkable changes in the electrical conductivity and oxygen permeation flux.

Preparation of TiO_2/ITO film by liquid phase deposition and its photoelectrocatalytic activity for degradation of 4-aminoantipyrine

A thin layer of TiO2 film was deposited on ITO surface via the liquid phase deposition （LPD） process. The photocurrent and electrochemical impedance spectroscopy （EIS） measurements indicated that the as-prepared LPD TiO2/ITO film had an excellent photoelectrochemical performance, which showed a sensitive and rapid response to the UV irradiation. The photogenerated electron-hole pairs could be effectively separated by applying an external bias to the TiO2 film electrode. The LPD TiO2/ITO film was employed to study the photoelectrocatalytic （PEC） degradation of 4-aminoantipyrine. Compared with other techniques, the PEC technique based on such a LPD film electrode had a synergetic effect for 4-aminoantipyrine degradation. When the applied bias potential was＋0.8 V and the supporting electrolyte concentration of Na2SO4 was 0.1 mol/L, the highest degradation efficiency within 120 min could reach 95%for 0.1 mmol/L 4-aminoantipyrine solution at pH 2.0.

Fabrication and Electrical Properties of Titanium Oxide by Thermally Oxidizing Titanium on Silicon

Polycrystalline titanium oxide films are fabricated on silicon by thermally oxidizing titanium.The current- voltage and capacitance- voltage characteristics of the Ag/Ti Ox/Si/Ag capacitors are m easured.The thickness of the titanium oxide films arranges from15 0 nm to2 5 0 nm,and their dielectric constants are within40～ 87.As the oxida- tion tim e is shortened,the fixed charges of the titanium oxide films become less and the leakage current characteris- tics becom e better.

Formation and capacitance properties of Ti-Al composite oxide film on aluminum

Al specimens were covered with TiO2 film by sol-gel dip-coating and then anodized in ammonium adipate solution.The structure,composition and capacitance properties of the anodic oxide film were investigated by transmission electron microscopy (TEM),Auger electron spectroscopy (AES),X-ray diffractometry (XRD) and electrochemical impedance spectroscopy (EIS).It was found that an anodic oxide film with a dual-layer structure formed between TiO2 coating and Al substrate.The film consisted of an inner Al2O3 layer and an outer Ti-Al composite oxide layer.The thickness of layers varied with the number of times of sol-gel dip-coating.The capacitance of anodic oxide films formed on coated specimens was at most 80% higher than that without TiO2.In film formation mechanism,it was claimed that the formation of composite oxide film was mainly affected by the structure of micro-pores network in TiO2 coating which had an influence on Al3+ and O2? ions transport during the anodizing.

A Novel Multi-Tube Photoreactor with UV Light and Immobilized TiO_2 Thin Film for Water Treatment

A novel multi-tube photoreactor with 0.0188m3 valid reaction volume was constructed in pilot-scale. This rectangular reactor consisted of 13 regularly distributed silica glass tubes coating with TiO2 thin film photo-catalyst. Total active area of TiO2 thin film is 0.3916m2. The ratio of surface area to volume achieves 20.8m-1. Photocatalytic experiment of phenol red demonstrates that the apparent reaction rate constant (k) is 0.074 65 h-1 and 0.16502h-1 for reaction system with and without micro-bubbles mixing. The corresponding apparent quantum efficiency (a) is 8.1771 X 10-7g.J-1 and 4.9036 x 10-7g-J-1, respectively. COD value of reactant could decrease to 17mg.L-1 and high performance liquid chromatography (HPLC) only shows two absorption peaks in 24 h pho-tocatalytic process time, so this photoreactor has good photomineralization effect. Experimental results reveal that photocatalytic destruction of organics is possible by using the multi-tube photoreactor.

A Novel Dense Mixed-Conducting Membrane for Oxygen Permeation

Perovskite type SrCo0.4Fe0.6O3-δ(SCF) membrane and a novel perovskite-related ZrO2 doped SrCo0.4Fe0.6O3-δ(SCFZ) membrane were successfully prepared by isostatic pressing. The sintered membranes were characterized by high-temperature X-ray diffraction (HTXRD) and energy dispersive spectroscopy (EDS). The oxygen permeabilities of membranes have been measured in the temperature range of 923 K to 1243 K. The oxygen permeation flux at 1123K and activation energy of SCFZ membrane with the thickness of 2mm are respectively 2.68×10^-7 mol·cm^-2·min^-1 and 97.76 kJ·mol^-1. The results of HTXRD in argon atmosphere and the oxygen permeation experiment indicate that the SCFZ membrane is stable at elevated temperature and low oxygen partial pressure.

Hybrid functional IrO_2-TiO_2 thin film resistor prepared by atomic layer deposition for thermal inkjet printheads

IrO2-TiO2 thin films were prepared by atomic layer deposition using Ir（EtCp）（COD） and titanium isopropoxide （TTIP）. The resistivity of IrO2-TiO2 thin films can be easily controlled from 1 500 to 356.7 μΩ·cm by the IrO2 intermixing ratio from 0.55 to 0.78 in the IrO2-TiO2 thin films. The low temperature coefficient of resistance（TCR） values can be obtained by adopting IrO2-TiO2 composite thin films. Moreover, the change in the resistivity of IrO2-TiO2 thin films was below 10% even after O2 annealing process at 600 ℃. The step stress test results show that IrO2-TiO2 films have better characteristics than conventional TaN08 heater resistor. Therefore, IrO2-TiO2 composite thin films can be used as a heater resistor material in thermal inkjet printhead.

TiO2 Nanoparticles Produced by Electric-Discharge-Nanofluid-Process as Photoelectrode of DSSC

Self-made TiO2 nanoparticles were used as photoelectrode material of dye sensitized solar cell. The TiO2 thin film coats through spreading nanoparticles evenly onto the ITO glass via self-made spin-heat platform, and then TiO2 thin film is soaked in the dye N-719 more than 12 h to prepare the photoelectrode device. The TiO2 nanoparticles produced by electric-discharge-nanofluid-process have premium anatase crystal property, and its diameter can be controlled within a range of 20-50 nm. The surface energy zeta potential of nanofluid is from -22 mV to -28.8 mV, it is a stable particle suspension in the deionized water. A trace of surfactant Triton X-100 put upon the surface of ITO glass can produce a uniform and dense TiO2 thin film and heating up the spin platform to 200 oC is able to eliminate mixed surfac-tant. Self-made TiO2 film presents excellent dye absorption performance and even doesn＇t need heat treatment procedure to enhance essential property. Results of energy analysis show the thicker film structure will increase the short-circuit current density that causes higher conversion efficiency. But, as the film structure is large and thick, both the open-circuit voltage and fill factor will decline gradually to lead bad efficiency of dye-sensitized solar cell.

Fabrication of nanoporous TiO_2 films with novel surface morphology on conducting glass(FTO) substrate

The crystalline structure and surface morphology of TiO2 semiconductor coating play an important role in the conversion efficiency of dye-sensitized solar cells. In order to obtain TiO2 coating with controllable morphology and high porosity, nanoporous TiO2 films were fabricated on conducting glass （FTO） substrates, Ti thin films （1.5-2 gin） were deposited on conducting glass （FTO） substrates via the DC sputtering method, and then electrochemically anodized in NH4F/ethylene glycol solution. The crystalline structure and surface morphology of the samples were characterized by X-ray diffraction （XRD） and field emission scanning electron microscopy （FESEM）, respectively. The influences of anodizing potential, electrolyte composition, and pH value on the surface morphology of nanoporous TiO2 films were extensively studied. The growth mechanism of nanoporous TiO2 films was discussed by current density variations with anodizing time. The results demonstrate that nanoporous TiO2 films with high porosity and three-dimensional （3D） networks are observed at 30 V, when the NH4F concentration in ethylene glycol solution is 0.3% （mass fraction） and the electrolyte pH value is 5.0.

Effects of Sintering Atmosphere on the Microstructure and Surface Properties of Symmetric TiO2 Membranes

The effects of sintering atmosphere on the properties of symmetric TiO2 membranes are studied with regard to sintering behavior, porosity, mean pore size, surface comPosition. and surface charge properties. The exerimental results show that the symmetric TiO2 membranes display better sintering activity in the air than in argon, and the mean pore diameters and porosities of the membrane sintered in argon are higher than those of the membrane sintered in the air at the same temperature. The surface compositions of the symmetric TiO2 membrane sintered in the air and in argon at different temperatures, as studied by X-ray photoelectron spectroscopy, are discussed in terms of their chemical composition, with particular emphasis on the valence state of the titanium ions. The correlation between the valence state of the titanium ions at the surface and the surface charge properties is examined.It is found that the presence of Ti^3＋, introduced at the surface of the symmetric TiO2 membranes by sintering in a lower partial pressure of oxygen, is related to a significant decrease in the isoelectric point. TiO2 with Ti^4＋ at the interface has an isoelectric point of 5.1, but the non-stoichiometric TiO2-x with Ti^3＋ at the interface has a lower isoelectric point of 3.6.

Preparation and Characterization of a Perovskite-type Mixed Conducting SrFe0.6Cu0.3Ti0.1O3-δ Membrane for Partial Oxidation of Methane to Syngas

Dense membrane with the composition of SrFe0.6Cu0.3Ti0.1O3-δ （SFCTO） was prepared by solid state reaction method. Oxygen permeation flux through this membrane was investigated at operating temperature ranging from 750℃ to 950℃ and different oxygen partial pressure. XRD measurements indicated that the compound was able to form single-phased perovskite structure in which part of Fe was replaced by Cu and Ti. The oxygen desorption and the reducibility of SFCTO powder were characterized by thermogravimetric analysis and temperature programmed reduction analysis, respectively. It was found that SFCTO had good structure stability under low oxygen pressure at high temperature. The addition of Ti increased the reduction temperature of Cu and Fe. Performance tests showed that the oxygen permeation flux through a 1.5 mm thick SFCTO membrane was 0.35-0.96 ml·min ^-1·cm^-2 under air/helium oxygen partial pressure gradient with activation energy of 53.2 kJ·mol^-1. The methane conversion of 85%, CO selectivity of 90% and comparatively higher oxygen permeation flux of 5 ml·min^-1·cm^- 2 were achieved at 850℃, when a SFCTO membrane reactor loaded with Ni-Ce/Al2O3 catalyst was applied for the partial oxidation of methane to syngas.

Corrosion Behavior of Anodic Oxidized TiO_2 Film in Seawater

TiO2 films were formed on metallic titanium substrates by the anodic oxidation method in H2SO4 solution under the 80V D.C..Phase component and microstructure were characterized by X-ray diffraction (XRD) and scanning electron microscopy (SEM).Water contact angles on titanium oxide film surface were measured under both dark and sunlight illumination conditions.Corrosion tests were carried out in seawater under different illumination conditions by electrochemistry impedance spectrum (EIS) and polarization curves.The result showed that the TiO2 film prepared by the anodic oxidation method was anatase with a uniform structure and without obvious pores or cracks on its surface.The average water contact angle of the film was 116.4? in dark, in contrast to an angle of 42.7? under the UV illumination for 2 hours, which demonstrates good hydrophobic property.The anti-corrosion behavior of the TiO2 film was declining with the extended immersion time.Under dark conditions, however, the hydrophobic TiO2 film retarded the water infiltrating into the substrate.The impedance changed slowly and the corrosion current density was 2 orders of magnitude lower than that with the film illuminated by sunlight.All of those mentioned above indicate that the TiO2 film possesses much better performance under dark condition, and it can be applied as an engineering material under dark seawater environment.

Self-Organizing Evolution of Anodized Oxide Films on Ti-25Nb-3Mo-2Sn-3Zr Alloy and Hydrophilicity

In the present work,hierarchical nanostructured titanium dioxide(TiO2) films were fabricated on Ti-25Nb-3Mo-2Sn-3Zr(TLM) alloy for biomedical applications via one-step anodization process in ethylene glycolbased electrolyte containing 0.5wt% NH4F.The nanostructured TiO2 films exhibited three distinct types depending on the anodization time:top irregular nanopores(INP)/beneath regular nanopores(RNP),top INP/middle regular nanotubes(RNT)/bottom RNP and top RNT with underlying RNP.The evolution of the nanostructured TiO2 films with anodization time demonstrated that self-organizing nanopores formed at the very beginning and individual nanotubes originated from underlying nanopore dissolution.Furthermore,a modified two-stage self-organizing mechanism was introduced to illustrate the growth of the nanostructured TiO2 films.Compared with TLM titanium alloy matrix,the TiO2 films with special nano-structure hold better hydrophilicity and higher specific surface area,which lays the foundation for their biomedical applications.

Surface characteristics and structure of oxide films containing Ca and P on Ti substrate

The oxide films were obtained in an electrolyte of calcium glycerphosphate (Ca-GP) and calcium acetate (CA) by microarc oxidation (MAO). The oxide films displayed a porous and rough structure on the film surface, and the roughness tended to increase with increasing voltage of microarc oxidation. The oxide film exhibited a uniform coating and tends to be well boned to the substrate. The thickness of oxide films depended on the final voltage at a constant concentration of electrolyte solution. Ca and P were also incorporated into the oxide film during the microarc oxidation process. It was found that the electrolyte of calcium glycerphosphate (Ca-GP) and calcium acetate (CA) was suitable for microarc oxidation to form oxide film containing Ca and P on Ti substrate. The concentration of Ca and P were 11.6 at% and 6.4 at%, respectively, when microarc oxidation was performed in the electrolyte of 0.06 M Ca-GP and 0.25 M CA at current density 50 A/m^2 and final voltage 350 V. The composition of the Ca, P and Ti changed during depth profiling. The crystalline phases were only anatase when final voltage was below 300 V and rutile was presented when voltage was up to 350 V. The microstructure, phase structure and phase composition were investigated by scanning electron microscopy (SEM), atomic force microscope (AFM), energy dispersive X-ray microanalyser (EDX), and X-ray diffraction (XRD).