金红石型纳米TiO2紫外屏蔽性能的相关应用及改性研究

金红石型纳米TiO2对可见光的透射性强,具有极好的吸收、散射紫外线能力,可作为紫外屏蔽剂广泛应用于涂料、化妆品、纺织、木材加工等行业.但纳米TiO2同时也具有光催化性能,是有机基体发生光氧化的催化剂,且在有机基体中的分散性和稳定性不好,需经表面处理以解决这些问题.本文针对金红石型纳米TiO2防紫外性能的相关应用、存在的...     

A study of ferrocyanide sorbents on hydrated titanium dioxide support using physicochemical methods

The paper describes how the conditions of preparing ferrocyanides on hydrated titanium dioxide support affect the surface texture of the resulting materials, their elemental and phase composition, and their ability to sorb cesium. The sorbents prepared under the optimal conditions exhibited increases specificity to Cs (K _d = 10^5.6±1.0 ml g⁻¹) and high capacity (no less than 270 mg g⁻¹).     

医用钛金属材料表面改性研究

由于具有优良的力学、生物学、安全性等性能，钛及其合金被日益广泛的应用于人体硬组织的修复、替换。然而其表面硬度低、耐磨性差、生物惰性等是作为医用材料不容忽视的问题，为了改善这些性能，需要对钛合金表面进行改性处理。综合评述了多种表面处理技术的优点，指出对多种表面处理技术进行综合应用是今后的研究方向。     

Surface modification of elongated one-dimensional titanium dioxide structures with ferromagnetic nanoparticles

Nanostructured TiO₂ in the form of elongated one-dimensional structures having a highly ordered layered morphology, with cobalt-containing agglomerates on their surface, has been prepared by hydrothermal treatment of CoTiO₃ powder in the presence of chitosan, a bioactive natural polymer. The synthesis products have been characterized by scanning electron microscopy, transmission electron microscopy, IR spectroscopy, X-ray diffraction, elemental analysis, and magnetic measurements. The structures have been shown to be up to several microns in length, and their typical width ranges from 100 to 400 nm. The one-dimensional structures retain high thermal stability at calcination temperatures of up to 800°C. After vacuum heat treatment at 600°C and above, the nanostructured material possesses anomalously high ferromagnetic characteristics.     

Surface modification of a novel porous titanium dioxide/glass composite

A novel technique is used to produce an open porous titanium dioxide/glass composite, named Ecopore, with promising structural and biological properties for the development as a bone graft. This study aims at a fast and lasting integration of the new material by means of biochemical surface modification. Surface etching of Ecopore, aminosilanization and covalent coupling of the cellular attachment mediator fibronectin was employed as modification strategy. In a comparison of different etching procedures, alkaline etching led to the highest density of amino functions after subsequent aminosilanization. Fibronectin was immobilized using a bifunctional aminoreactive PEG‐linker. This protein coating improved the attachment of human osteoblast‐like cells (HOB) on non‐porous Ecopore as displayed by vital staining. XTT metabolism assays indicated an enhanced HOB growth in the initial phase of cultivation on fibronectin‐coated versus non‐coated specimens. In a first feasibility study, cultivation of HOB on coated porous Ecopore cylinders with a median pore size diameter of 130 μm showed that cellular growth was uniform and dense on the external surface of the specimen, but was sparse in the interior pore system. Ecopore batches with larger pores will be modified and investigated in vitro and in vivo in the next step of the study.     

On the surface photoconductivity of sintered titanium dioxide pellet

Surface photoconductance of sintered titanium dioxide (TiO₂) pellet has been studied at room temperature (306 K) and above (upto 475 K). Within the temperature range studied, the conduction in dark has been found purely extrinsic with the activation energies of 0.07 and 0.24 eV. Moderately slow growth of photocurrent at all temperatures indicated the presence of traps. Photosensitivity of the sample was found to increase continuously with the rise of sample temperature. Analysis of the photoconductive decay of the sample has revealed the existence of carriers with two different relaxation times (₁ and ₂) which varied with the sample temperature in a peculiar fashion.     

Molecular modelling of protein adsorption on the surface of titanium dioxide polymorphs

This paper reports a molecular modelling study of the adsorption of protein subdomains with unlike secondary structures on different surfaces of ceramic titanium dioxide (TiO(2)), forming a passivating film on titanium biomaterials that provides the interface between the bulk metal and the physiological environment, affecting its biocompatibility and performance. Using molecular dynamics methods, we study the effect of the nanoscale structure of the common TiO(2) polymorphs (rutile, anatase and brookite) on the adsorption of an albumin subdomain and on two connected fibronectin modules, respectively containing α-helices and β-sheets. We find that the larger protein subdomain shows a stronger adsorption, as expected because of its size, but also that the three surfaces behave differently. In particular, brookite shows the weakest adsorption, whereas anatase leads to the strongest intrinsic adsorption, in particular for the fibronectin modules. Moreover, the simulations indicate a significant conformational change of the adsorbed protein subdomains with extensive surface nanopatterning. These results show that classical molecular dynamics methods can provide useful information about the influence of nanostructure and topology on protein physisorption at a fixed surface chemistry.     

Deposition and modification of titanium dioxide thin films by filtered arc deposition

Thin films of titanium dioxide have been deposited on glass substrates and conducting (100) silicon wafers by filtered arc deposition (FAD). The influence of the depositing Ti⁻ energy, substrate types and substrate temperature on the structure, density, mechanical and optical properties have been investigated. The results of X-ray diffraction (XRD) showed that with increasing substrate bias, the film structure on silicon substrates changes from anatase to amorphous and then to rutile phase without auxiliary heating, the transition to rutile occurring at a depositing particle energy of about 100 eV. However, in the case of the glass substrate, no changes in the structure and optical properties were observed with increasing substrate bias. The optical properties over the range of 300–800 nm were measured using spectroscopic elliosometery, and found to be strongly dependent on the substrate bias, film density and substrate type. The refractive index values of the amorphous, anatase and rutile films on Si were found to be 2.56, 2.62 and 2.72 at a wavelength of 550 nm, respectively. The hardness and elastic modulus of the films were found to be strongly dependent on the film density. Measurements of the mechanical properties and stress also confirmed the structural transitions. The hardness and elastic modulus range of TiO₂ films were found to be between 10–18 and 140–225 GPa, respectively. The compressive stress was found to vary from 0.7 to 2.6 GPa over the substrate bias range studied. The composition of the film was measured to be stoichiometric and no change was observed with increasing substrate bias. The density of the film varied with change in the substrate bias, and the density ranged between 3.62 and 4.09 g/cm³.     

Effect of organic surface agents on properties of hydrated cement compacts

Summary This paper reports the treatment of bottle-hydrated portland cement with organosilanes, oleic acid and octadecylamine intended to reduce the sorption of water and the corresponding dimensional changes. Compacts were made from the treated hydrated cement powder to simulate cement paste and allow measurements of sorption-dimensional change characteristics and microhardness. It was found that organochlorosilanes are not suitable for the treatment because the HCl released during the reaction produced undesirable side effects and in some cases increased the adsorption and expansion of the cement. Hexamethyldisilazane was more effective, reducing odsorption by 10 to 20%. Oleic acid was effective at concentrations as high as 25% by weight, but serious loss in mechanical property of microhardness was experienced.

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Résumé On expose le traitement de ciment Portland hydraté par des organosilanes, l’acide oléique et l’octadecylamine, afin de réduire la sorption d’eau et les variations dimensionnelles, correspondantes. Les mesures de ces variations dimensionnelles et de la microdureté ont été faites sur des éprouvettes de poudre de ciment hydraté traité et compacté, comme modèle de la pate de ciment hydraté. Il est apparu que les organochlorosilanes ne conviennent pas à cause de l’acide chlorhydrique produit durant la réaction, qui entra?ne des effects secondaires indésirables, et même, dans certains cas, augmente l’adsorption d’eau, et l’expansion du ciment. Plus efficace, l’hexamethyldisilazane réduit l’adsorption de 10 à 20% et l’expansion de 20 à 30%. L’acide oléique agit à des concentrations en poids de l’ordre de 25%, mais on a constaté une importante diminution des propriétés mécaniques et de la microdureté.

     

ZnS在TiO2纳米管上的分散对其光催化降解染料废水的影响

水热法制备了TiO2纳米管,并采用简单加热回流的方法制备了ZnS/TiO2纳米复合材料。采用TEM、XRD分析手段对产物进行表征,并对其光催化降解酸性玫瑰红B(AR)染料废水进行了研究。考察了反应物供给速率、硫化锌复合量、催化剂稳定性、光照对光催化降解效果的影响。研究表明控制反应物供给速率和硫化锌的负载量可使硫化锌在二氧化钛纳米管表面均匀分散。当染料废水初始浓度为10mg/L,ZnS:TiO2=8:1时,ZnS/TiO2复合材料光催化活性最高。且催化剂稳定性较好。     

TiO_2包覆无机矿物粉体的制备

选用无机矿物粉体为基料,官能化金红石型TiO_2浆液为成膜物质,KM-10为官能化助刺,制备了无机矿物粉体/TiO_2复合粒子.采用正交设计实验法,探讨了不同组分的配比及无机矿物粉体的种类对合成包覆产物遮盖力的影响,最佳组分的重量配比为:m(TiO_2浆液):m(KM-10):m(硅酸铝)=0.25:0.05:1,包覆产物的遮盖力可达59.9g/cm~2.产物FTIR结构分析表明,TiO_2是通过化学键包覆在无机矿物粉体表面;经TEM分析表明,产物呈球形结构,分散性良好,平均粒径约为1.0μm.     

Effect of niobium on the structure of titanium dioxide thin films

This paper reports the effect of niobium on the structure of titanium dioxide (TiO₂) thin films deposited on glass. The results obtained indicated that the direct current (DC) co-sputtering of Ti and Nb onto glass substrates in the presence of oxygen results in the formation of Nb-doped anatase thin films with strong preferential orientation. In the concentration range between 0 and 40 at.% Nb, niobium is incorporated into the TiO₂ lattice according to a substitution mechanism, entering Ti sites in the cation sub-lattice. No evidence exists for a solubility limit < 40 at.% of Nb under the applied deposition conditions, however, it is not believed that an equilibrium situation prevails. Lattice charge compensation was concluded to occur by the formation of cation vacancies for samples with up to 10 at.% Nb, and by Ti³⁺ or Nb⁴⁺ ions for the samples with ≥ 15 at.% Nb, the latter in conjunction with cation vacancy compensation.     

The relationship of surface roughness and cell response of chemical surface modification of titanium

Implant surface topography influences osteoblastic proliferation, differentiation and extracellular matrix protein expressions. Previous researches proved that chemical surface modification of titanium implants could be used to improve Bone-to-implant contact. In this study, the surface topography, chemistry and biocompatibility of polished titanium surfaces treated with mixed solution of three acids containing HCl, HF and H(3)PO(4) with different etched conditions for example concentration, time and addition of calcium chloride were studied. Osteoblast cells (MG-63) were cultured on different groups of titanium surfaces. In order to investigate titanium surfaces, SEM, AFM and EDS analyses were carried out. The results showed that surfaces treated with HCl-HF-H(3)PO(4) had higher roughness, lower cytotoxicity level and better biocompatibility than controls. Moreover, addition of calcium chloride into mixed solution of three acids containing HCl, HF and H(3)PO(4) is an important, predominant and new technique for obtaining biofunction in metals for biomedical use including dentistry.     

Effect of heat treatment on the structure of titanium dioxide films

The development of nanocrystalline phases during isothermal annealing of titanium dioxide films deposited by reactive magnetron sputtering at various rates onto silica glass substrates has been studied. It is established that the heat treatment at temperatures within 500–700°C in air or in vacuum leads to significantly different results, depending on the initial crystalline structure of as-deposited films.     

Hepatocyte spheroid formation on a titanium dioxide gel surface and hepatocyte long-term culture

The cell morphology and expression of differentiated functions of primary rat hepatocytes on a titanium dioxide (TiO₂) gel surface were investigated. Polystyrene culture dishes were coated with TiO₂ gel by spin-coating an ethanol solution of titanium n-butoxide, hydrolyzing in a humidity chamber and drying with nitrogen gas. The TiO₂ gel layer formed on the polystyrene dishes was transparent and robust, and its surface was quite flat. Rat hepatocytes inoculated on the TiO₂ gel-coated polystyrene dishes gradually accumulated with increasing culture time, and then spontaneously formed many hepatocyte spheroids at 90 ± 21 μm diameter from about 3 days of culture. The diameter of the spheroids increased during the culture, and was 151 ± 43 μm at 14 days of culture. Ammonia removal and albumin secretion by hepatocytes on the TiO₂ gel-coated polystyrene dishes were maintained at a high level for at least 14 days of culture compared with on a type I collagen-coated dish and a non-coated polystyrene dish. These results indicate that TiO₂ gel is an adequate material for hepatocyte spheroid formation and long-term culture of spheroids.     

STM observation of zinc(II) bridled chiroporphyrin molecules on titanium dioxide surface

Zinc bridled chiroporphyrin (ZnBCP-8) molecules on a rutile titanium dioxide (TiO₂)(110)-(1 × 1) surface were successfully observed by scanning tunneling microscopy (STM) under ultrahigh vacuum conditions. The molecules were selectively adsorbed on the surface apparently due to a molecule-substrate interaction. The origin of the interaction is thought to be Coulomb force between molecule and oxygen vacancy on the TiO₂ surface. STM imaging revealed a selective molecular orientation on the TiO₂(110)-(1 × 1) structure. These results support the possibility of manipulating molecules on the surface and constructing well designed molecular structures by controlling the molecular-substrate and intermolecular interactions.     

纳米结构形貌二氧化钛的制备及其气敏响应

为获得高灵敏度的纳米结构感知元件，对二氧化钛的形貌调控进行了研究．结果表明，TiO2粉体经适当的水热处理可获得高比表面积的纳米TiO2形貌．SEM和XRD结果显示处理效果明显．将该形貌的纳米TiO2用于传感器原理型器件的制备，室温下对有机挥发性气氛显示出快速响应．这为高灵敏度化学传感器及其阵列的研发提供了一简便的材料制备途径。     

刻蚀处理对钛表面形貌的影响

发展电化学刻蚀和化学刻蚀技术,对钛表面进行处理,并应用扫描电镜、X射线衍射方法对其表面进行表征,探讨电化学刻蚀钛表面形成微观结构的机理.结果表明,经刻蚀后钛表面形成了纳米级微观结构,提高了表面粗糙度,可增强生物材料涂层与钛基底的结合强度.     

Kinetics of <Superscript>99</Superscript>Мо sorption onto a sorbent based on hydrated titanium dioxide

The kinetics of ⁹⁹Мо sorption onto T-5 sorbent in the batch mode at different values of the stirring rate, temperature, and sorbent granule size was studied. All the experimental kinetic curves are described by a sum of two exponents. In the first time interval of phase contact, from 0 to 5–10 min, the sorption is controlled by external diffusion, and in the interval from 10 to 40 min the step of transformation of unsorbable Mo species into sorbable hydroxo species also becomes a rate-determining step (external kinetic control). In the final stage (time interval from 40 min to 2–3 h), the sorption occurs at the lowest rate, and the Mo diffusion in micropores and overcoming of electrostatic hindrance on the surface of titanium hydroxide pores become the most probable limiting steps. In sulfate solutions, the Mo sorption rate considerably decreases already in the first stage, and the external kinetic control becomes prevalent because of hindered redistribution of unsorbable sulfate complexes into sorbable hydroxo complexes. The controlling factor in the sulfate and nitrate solutions in the second stage is presumably the same.