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131.
Mariko Kusabe Hiromitsu Kozuka Satoru Abe Hiroshi Suzuki 《Journal of Sol-Gel Science and Technology》2007,44(2):111-118
Hydroxypropylcellulose (HPC)–titania hybrid thin films were prepared by sol–gel method where titanium tetraisopropoxide Ti(OC3H7
i
)4 was hydrolyzed under acidic conditions in the presence of HPC, followed by dip-coating and drying at 120 °C for 24 h. The
viscosity average molecular weight of HPC was 55,000–70,000 or 110,000–150,000, and the TiO2/(HPC + TiO2) mass ratio ranged from 0 to 1, which was calculated on the assumption that all Ti(OC3H7
i
)4 is converted into TiO2. The films were 0.35–1.0 μm thick, transparent in visible region and opaque in ultraviolet (UV) region, where the optical
absorption coefficient in UV region increased with increasing titania content. The refractive index increased with increasing
titania content, ranging from 1.6 to 1.8 for the hybrid thin films. The pencil hardness increased from 6B to 5H, the durability
in hot water significantly increased and the contact angle of water on films increased from 35° to 89° with increasing titania
content. Crack-free films could be deposited on organic polymer substrates irrespective of titania or HPC contents, where
cracking did not occur at higher HPC contents even when the substrate was bent. 相似文献
132.
The stability of spontaneous thin layers and thin layers formed upon cathodical polarization of Ti in KOH solutions have been
studied by potentiostatic and ellipsometric methods. At open circuit potential (OCP) the strongly adherent films, whose thickness
depends on the concentration of the KOH solution, were formed. During the cathodic polarization the transformation of these
films to weakly adsorbed precipitated layers on the electrode surface was observed. Comparing the theoretically computed curves
with the experimental Ψ vs Δ loci measured ellipsometrically, the complex indices of refraction and the thickness of the generated films, from 3.6
to 60 nm in 1 M KOH and from 36 to 105 nm in 5 M KOH (adherent to the electrode surface), were determined. At OCP the rate
of film growth increases with increasing the concentration of KOH solution. Cathodic polarizations change the chemical composition
and retard the rate of film growth. Based on the ellipsometric and electrochemical data the chemical compositions of the formed
films consisted of TiO2, Ti2O3, TiO2·H2O, Ti(OH)3 and TiOOH·nH2O. 相似文献
133.
J. Bates Q. Zhang L. Spiccia B. O. West 《Journal of Sol-Gel Science and Technology》1994,2(1-3):29-34
Two lead titanium oxyalkoxides with composition Pb2Ti4O2(O2CCH3)2(OC2H5)14 and Pb2Ti2O2(O2CCH3)2(OCH(CH3)2)8 have been isolated and characterised by elemental analysis, IR, 207Pb NMR and molecular weight measurements. X-ray structural analysis of the 1:2 complex confirmed the presence of two Pb2Ti2O units which are linked by a common Pb···Pb edge and are held together by alkoxide and acetate bridges. The acetate groups have migrated from the Pb to the Ti centres during the reaction. Hydrolysis of the 1:1 Pb/Ti complex produced clear gels providing the H2O/complex ratio was less than 4. Heat treatment of the gel results in loss of residual organics below 400°C. The XRD pattern indicates the presence of the pyrochlore and perovskite phases after heating at 500°C but the sample is poorly crystalline. Complete conversion to the perovskite phase of lead titanate occurs on heating to 600°C for 1 hour. Thin films of lead titanate were deposited by dip-coating a solution of this complex in isopropanol. Analyses of the films, carried out using electron microprobe, Scanning Auger Spectroscopy and Rutherford Backscattering, indicated that they were of excellent quality, crystalline after heating at 600°C and with relatively sharp substrate-coating interface. 相似文献
134.
Elena Laukhina Vladislava Tkacheva Salavat Khasanov Leokadia Zorina Jordi Gómez-Segura Angel Pérez del Pino Jaume Veciana Vladimir Laukhin Concepció Rovira 《Chemphyschem》2006,7(4):920-923
Temperature has great impact on the structure and size of the linked crystallites of the conducting topmost layer formed at the surface of a polycarbonate film via the reaction BEDT-TTF+IBr [BEDT-TTF=bis(ethylenedithio)tetrathiafulvalene]. We show that fine temperature control permits formation of a semiconducting topmost layer of alpha'-(BEDT-TTF)(2)(I(x)Br(1-x))(3) crystallites with either micro- or nanometre size, a result that opens a route to miniaturized conducting plastic materials. 相似文献
135.
Sandip Halder Theodor Schneller Rainer Waser Florian Thomas 《Journal of Sol-Gel Science and Technology》2007,41(3):203-207
Nickel thin films have been sputtered on standard Si/SiO2 substrates with TiO2 as an adhesive layer. The thermal stability of these substrates was analyzed. SEM images show an increase in grain size with
annealing temperature. They were found to be stable till 800°C, beyond which the nickel layer disintegrated. These substrates
were used for deposition of BaTiO3 and (Ba,Sr)TiO3 dielectric thin films under a reducing atmosphere. The dielectric thin films were processed with various pyrolysis and annealing
temperatures in order to optimize the dielectric properties. Increased pyrolysis temperatures showed an increase in the grain
size. Results on these nickelised substrates were finally compared with dielectric films deposited on platinized silicon substrates
under identical conditions but crystallized in an oxygen atmosphere. 相似文献
136.
Sumio Sakka 《Journal of Sol-Gel Science and Technology》1994,2(1-3):451-455
The present state of our knowledge on sol-gel coating films has been reviewed. A qualitative discussion is made on the limit of the film thickness which can be achieved in the sol-gel method and the factors affecting the film thickness. Considering that properties of the film are intimately related to the microstructure, types of microstructures accomplished by the sol-gel coating are introduced with examples. 相似文献
137.
纤维素/甲壳素共混膜的结构表征与抗凝血性能 总被引:20,自引:0,他引:20
以 6wt %NaOH 4wt%尿素为纤维素的新溶剂 ,采用溶液共混法制备出纤维素 甲壳素共混膜 ,为甲壳素在碱性溶液中制膜提供了新的方法 .红外光谱、X 射线衍射、扫描电镜和力学性能、抗凝血性能测试结果表明 ,共混膜中甲壳素含量低于 4 0wt%时 ,纤维素与甲壳素分子间具有良好的相容性 ;在纤维素中引入适量甲壳素可提高共混膜的抗张强度 ,共混膜的干、湿态抗张强度在甲壳素含量 10wt%时最大 ,其值分别为 89 1MPa和 4 3 7MPa ,比纯态纤维素膜的干、湿态抗张强度分别提高了 6 7%和 11 5 % ;甲壳素的引入可明显降低血小板在共混膜表面的粘附、凝聚与变性 ,增大共混膜的抗凝血参数 ,甲壳素含量达到 5 0wt%时 ,该共混膜具有良好的抗凝血性能 相似文献
138.
139.
The present work describes a novel method for the incorporation of Nile blue A into polyurethane foam matrix. This foam material was found to be very suitable for the extraction of metal ions from aqueous solutions. The characterization of Nile blue A grafted foam and the effect of halide concentration, pH, shaking time, extraction isotherm and capacity have been investigated. This foam material was found to be suitable for the separation and preconcentration of iron (III), zinc (II), cadmium (II) and mercury (II) from waste water. The extraction was accomplished in (15-20) minutes. Iron was separated from acid medium (2-4 M HCl), zinc from (3-5 M HCl), cadmium from (4-6 M HCl) as thiocyanate complexes and mercury was separated from (1-2 M HCl) as chloride. 相似文献
140.
Electropolymerized thin films of Co(III/II)- and Zn(II)-4,9,16,23-tetraaminophthalocyanine, immersed in solutions of relatively high pH, have been studied electro- and spectroelectrochemically. Cyclic voltammetry and chronocoulometry were used to characterize films deposited on glassy carbon electrodes. Spectroelectrochemistry and ellipsometry measurements were performed on indium tin oxide (ITO) surfaces coated with the zinc and cobalt complexes and correlated to the electrochemical information collected using glassy carbon electrodes. Studies at high pH are motivated by the efficient increase in luminol chemiluminescence at high OH− concentration, and by potential application in luminescence sensors. Although the films are not removed, some structural changes occur when they are exposed to solutions of high pH. In addition, an estimation of the number of monolayers has also been calculated. The atomic diameters of cobalt and zinc are very close in value, but the estimated number of monolayers, based on cyclic voltammetric data, for a given number of electropolymerization cycles is approximately four-fold higher in the zinc-based film. This would correspond to three-fold thicker films when zinc is the central metal ion. Ellipsometry measurements have been correlated with cyclic voltammetric data to confirm that film thickness varies among the different complexes, even though the conditions of electropolymerization are the same. 相似文献