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Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Cylinders, 2.8 mm in diameter and 6 mm in length which were produced from hot isostatically pressed titania (TI), titania-hydroxyapatite composite (TI/HA) and hydroxyapatite (HA) as well as commercially pure titanium (c.p. Ti), were implanted in the femurs of New Zealand white rabbits. The animals were killed at 1 and 3 months after implantation to study the development of bonding strength between the bone and the implant using the push-out test. The surface roughness and ion release of these materials in different solutions were also studied. Titania and titanium showed similar push-out strengths at 1 and 3 months after implantation. This indicates that bone has a similar response to titanium and titania due to the similarity of the surface constitute. Titania-hydroxyapatite composite showed a significant increase in bonding strength at 1 and 3 months after implantation compared with titania. A gap, < 2 microns wide, was observed by SEM at the bone-TI interface while the bone-HA interface was fully mineralized. No release of titanium ions from titania (rutile) was detected in the solutions used, including 0.1 M HCl, whilst release of titanium ions from c.p. Ti was measured in 0.02 M lactic acid and 0.1 M HCl. The results suggested that a further oxidation of titanium may improve the stability of c.p. Ti and that titania-based material may be a strong biocompatible ceramic suitable for medical applications.
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PMID:Behaviour of titanium and titania-based ceramics in vitro and in vivo. 838 56

Activated carbon cloth (ACC) was modified by the reaction between polar groups on its surface and metal alkoxides of titanium, silicon, aluminum and zirconium to enhance its capacitive deionization (CDI) performance. Incorporated state of metals and surface property of modified ACC were deduced from surface analysis results obtained using FE-SEM, XRD, XPS and zeta-potential meter. Titania was highly dispersed on the ACC surface with tetrahedral coordination, and the incorporated titania was effective to decrease physical adsorption of NaCl and to increase electric field adsorption, resulting in a significant enhancement of CDI performance. The negligible contribution of silica, alumina and zirconia modifications suggested that the small oxidation-reduction potential of titania was responsible for the enhancement of the electric field adsorption. Reversibility of adsorption and desorption operation on titania-modified ACC were also discussed relating to its CDI function.
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PMID:Improvement in capacitive deionization function of activated carbon cloth by titania modification. 1260 Mar 80

This study builds on previous results published on the synthesis and characterization of laponite-supported titania photocatalysts. Titania nanocrystals are prepared prior to addition to the clay dispersion, by a sol-gel synthesis incorporating a microwave hydrothermal step. In addition to previously examinations with XRD, TEM, and FT-IR, the samples are further characterized with SEM, 29Si NMR, and BET N2 sorption to gain additional insight into the effect of TiO2 concentration and surface area on the photoactivity of the samples.
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PMID:Laponite-supported titania photocatalysts. 1838 4

Titanium oxide films were prepared by RF magnetron sputtering onto glass substrates. The effects of RF power and deposition temperature on crystalline structure, morphology and energy gap were investigated, which were analyzed by X-ray diffraction, SEM and UV-Vis spectrometer, respectively. Results show that rutile phase is the favored structure during deposition. Applying RF power in the range of 50-250 W, the amorphous, rutile, and both rutile and anatase phases TiO2 films were obtained in sequence, while the content of anatase is similar in the range of 34-37% although the RF power increases. Increasing the deposition temperature, the anatase phase coexists in the rutile phase in the range of 100-200 degrees C, and the content of anatase increases from 20 to 41% with the deposition temperature. In addition, according to the morphology observation, the granulous surface is found in rutile phase while facetted surface in anatase phase when titanium oxide films deposited at various RF powers and substrate temperatures. The band gap energy of titanium oxide evaluated from (alphahv)1/2 versus energy plots show that the energy gap decreases with RF power increasing.
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PMID:Preparation of rutile and anatase phases titanium oxide film by RF sputtering. 1857 3

Vertically-oriented high aspect ratio titania nanotube bundles have been grown by a potentiostatic anodization of titanium sheet in fluoride-free electrolytes. The anodization conditions like the applied voltage were optimized for the synthesis of titania nanotubes in HClO4 and NaCl electrolyte. The resulting nanotubes have a length of about 30 microm, outer diameter about 40 nm, inner pore size of about 10 nm and the aspect ratio was 750:1 by anodization in 0.1 M perchloric acid of pH approximaately 1 at applied voltage of 20 V. While for nanotubes prepared in 0.3 M NaCl of pH 4.3, the length was above 50 microm with the aspect ratio of 1250:1. A method to increase the uniformity of nanotube was demonstrated by pretreatment the titanium sheet by (4 wt% HF + 5 M HNO3) solution prior to anodization. Titania nanotubes were prepared, for the first time, by anodization in aqueous H2SO4 electrolyte alone with tube length above 500 nm. Annealing studies were performed, on high aspect ratio Titania nanotube layers produced in HClO4 electrolyte, in the temperature interval of 300 to 550 degrees C. The XRD patterns and TEM data confirmed the formation of single anatase phase after annealing at 450 degrees C with perfect nanoubular structure. While the rutile titania phase starts to emerege after annealing at about 500 degrees C and the evidence for the appearance of rutile phase due to the oxidation of the underlying Ti metal at the interface between nanotube/Ti-metal was given. On the other hand, the nanotubular structure starts to destroy upon annealing temperature of approximate 550 degrees C by tube flattening and losing of roll-up characteristics as indicated in SEM images. The superior morphology of these high aspect ratio nanotubes and their rapid growth rate foreshadow a bright future in wide applications like dye-sensitized solar cells, water photolysis and nanobiomedical.
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PMID:Electrochemical growth of vertically-oriented high aspect ratio titania nanotubes by rabid anodization in fluoride-free media. 1943 43

Elaboration of mesoporous titanium oxide film supporting silver nanoparticles is described. Mesoporous titanium oxide films are characterized by TEM analysis. Titania films are infiltrated with a silver salt solution and chemical reduction treatments are performed using either a NaBH(4) or a formaldehyde solution. Infiltrated films are then characterized by TEM, SEM, AFM, UV-visible spectroscopy, X-ray diffraction, and Rutherford Backscattering Spectrometry (RBS). The utilization of a mesoporous titania substrate allows to control the nanoparticle size and the interparticle distance. RBS experiments provide the evidence that NaBH(4) treatment induces a strong accumulation of silver nanoparticles in the subsurface of the layer, while formaldehyde treatment induces the formation of silver nanoparticles embedded into almost the whole depth of the titania film. Large silver nanocrystals are also formed at the film surface whatever the reducer used. A broad visible absorption band related to the surface plasmon resonance (SPR) is obtained in both cases and is strongly red-shifted compared to the SPR obtained for silver nanoparticles inside a silica matrix. Moreover, irradiation with visible light causes the photooxidation of silver nanoparticles by titania and a complete discoloration of the material. The photooxidation is related to a drastic decrease in the silver nanoparticle size and is found to be reversible, particularly in the case of the material obtained by the formaldehyde reduction.
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PMID:Chemical growth and photochromism of silver nanoparticles into a mesoporous titania template. 2006 16

Titanium dioxide thin films have been synthesized by sol-gel spin coating technique on glass and silicon substrates with and without surfactant polyethylene glycol (PEG). XRD and SEM results confirm the presence of nano-crystalline (anatase) phase at an annealing temperature of 300 degrees C. The influence of surfactant and annealing temperature on optical properties of TiO(2) thin films has been studied. Optical constants and film thickness were estimated by Swanepoel's (envelope) method and by ellipsometric measurements in the visible spectral range. The optical transmittance and reflectance were found to decrease with an increase in PEG percentage. Refractive index of the films decreased and film thickness increased with the increase in percentage of surfactant. The refractive index of the un-doped TiO(2) films was estimated at different annealing temperatures and it has increased with the increasing annealing temperature. The optical band gap of pure TiO(2) films was estimated by Tauc's method at different annealing temperature.
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PMID:Influence of surfactant and annealing temperature on optical properties of sol-gel derived nano-crystalline TiO2 thin films. 2007 Dec 16

This study reports on the use of an atmospheric plasma technique to incorporate metal oxide nanoparticles into nm thick siloxane coatings. Titanium dioxide (TiO2) particles with diameters of 30-80 nm, were mixed with a number of different siloxanes-polydimethylsiloxane, hexamethyldisiloxane and tetraethylorthosilicate (TEOS). The TiO2/TEOS mixture was found to give the most stable suspension, possibly due to the higher surface tension of TEOS compared with the other siloxanes. TiO2/TEOS mixtures with 2 to 10% by weight of the metal oxide were prepared and were then nebulised into a helium/oxygen atmospheric plasma. Polyethylene terepthalate (PET) and silicon wafer substrates were passed through this plasma using a reel-to-reel substrate manipulation system. SEM combined with EDX was used to examine the distribution of the metal oxide particles in the resultant coatings. The TEOS coating thickness without TiO2 addition was 9 nm. The composite coating consisted of a relatively homogeneous distribution of small agglomerates of the TiO2 nanoparticles in TEOS. A linear increase in the titanium surface concentration was observed with increase in the quantity of TiO2 added into the siloxane precursor. The chemical functionality of the siloxane coating was examined using FTIR spectroscopy and no significant spectrum differences was observed with the incorporation of the different concentrations of TiO2 into the polymer. There were also no changes observed in coating surface energy with TiO2 incorporation. Coating morphology was examined using optical profilometry and surface roughness (Ra) values increased from typical values of 0.8 nm for the TEOS coating to 4.1 nm for the TiO2/TEOS coating. The adhesion of the deposited coatings was compared using fragmentation tests. These were carried out through uniaxial tensile loading. The coating cracking pattern after applied strain of 20% was not observed to change significantly with the addition of TiO2 into the siloxane.
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PMID:Effect of titanium oxide nanoparticle incorporation into nm thick coatings deposited using an atmospheric pressure plasma. 2035 95

The purpose of this study was to determine whether the brushing durability of a titanium dioxide coating on a polymethyl methacrylate (PMMA) substrate was improved by prior treatment with an acryloxypropyl trimethoxysilane-based agent. Titanium dioxide coatings were obtained by spray-coating substrates with or without prior treatment. Structure was investigated using IR, SEM, and an EPMA. Effect on durability against brushing was determined with a brush-wear test machine utilizing a commercial denture brush. A thin layer comprised of siloxane and TiO(2) was formed on a PMMA substrate by prior treatment with an acryloxypropyl trimethoxysilane-based agent and spray-coating of TiO(2). Prior treatment demonstrated improved stability against brushing, whereas the titanium coating was removed after less than 1x10(5) brushing cycles without prior treatment. This suggests that prior treatment with an acryloxypropyl trimethoxysilane-based agent would confer improved durability against brushing-induced stress on a TiO(2) coating in its application to dentures.
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PMID:Improved brushing durability of titanium dioxide coating on polymethylmethacrylate substrate by prior treatment with acryloxypropyl trimethoxysilane-based agent for denture application. 2037 19

Titanium dioxide nanopowders doped with different amounts of Fe ions were prepared by coprecipitation method. Obtained materials were characterized by structural (XRD), morphological (TEM and SEM), optical (UV/vis reflection and photoluminescence, and Raman), and analytical techniques (XPS and ICP-OES). XRD analysis revealed rutile crystalline phase for doped and undoped titanium dioxide obtained in the same manner. Diameter of the particles was 5-7 nm. The presence of iron ions was confirmed by XPS and ICP-OES. Doping process moved absorption threshold of TiO(2) into visible spectrum range. Photocatalytic activity was also checked. Doped nanopowders showed normal and up-converted photoluminescence.
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PMID:Synthesis and Characterization of Rutile TiO(2) Nanopowders Doped with Iron Ions. 2059 42


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