Papers by Keyword: Sol-Gel Method

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Authors: Lidia Ciołek, Joanna Karaś, Andrzej Roman Olszyna, Ewa Zaczyńska, Anna Czarny, Bogusława Żywicka, Krzysztof Szamałek
Abstract: The research of obtained bioglasses in the form of silver-containing powders were presented in this paper. The research conducted in order to determine antimicrobial activity under in vitro conditions of bioglasses. The results confirmed that these bioglasses Z-5, Z-8 and B-I inhibit the growth of most micro-organisms during the tested period and could be used in surgical treatment of the most advanced parodontium illnesses.
Authors: Bing Tao Tang, Xi Xi Zheng, Mei Ge Qiu, Chao Jia, Shu Fen Zhang
Abstract: 1-Octadecanol/SiO2 hybrid material, as a novel form-stable phase change material for thermal energy storage, was prepared via the sol-gel method. The crystallographic, phase-change, structural, and thermal stability properties of the samples were well characterized by X-Ray Powder Diffraction (XRD), Differential Scanning Calorimetry (DSC), Fourier transform infrared spectroscopy (FT-IR), and thermal gravimetry (TG). The results indicated that the 1-octadecanol/SiO2 hybrid material showed typical form-stable phase transition properties, e.g. suitable transition temperature (Tr=56.4 °C), high transition enthalpy (ΔH≥120.8 J/g) and good thermal stability. It is a functional hybrid material with good energy storage effect, and the heat storage mechanism of 1-octadecanol/SiO2 is the transfer between crystalline and amorphous states of the phase change component 1-octadecanol, and the silica serving as “cage-skeleton”, restricted the molecular chain of the 1-octadecanol’s free movement at high temperature. Thus, 1-octadecanol/SiO2 hybrid material can keep its solid state in the transition processing.
Authors: Ming Jing Wang, Hui Ming Ji, Ya Lu Chen, Qian Qian Jia
Abstract: ε-Fe2O3 is a rare and metastable iron (III) oxide phase. ε-Fe2O3/SiO2 composites were prepared by combining the reverse-micelle and sol-gel methods. An appropriate amount of Ba2+ was needed in this system to promote the formation of ε-Fe2O3 nanorods in SiO2. The size of nanorods varied with different Ba2+ addition amount and sintering procedure. Then pure ε-Fe2O3 nanorods were obtained after stripping SiO2 by etching due to NaOH aqueous solution. The as-synthesized ε-Fe2O3 nanorods were discussed using X-ray diffraction (XRD), scanning electron microscope (SEM) and transmission electron microscopy (TEM). Interestingly, metastable ε-Fe2O3 nanorods showed a promising performance for the response for ethanol, compared with the stable phases of α-Fe2O3 and γ-Fe2O3. It indicates that nanostructure ε-Fe2O3 (including ε-Fe2O3 nanorods) could be a valuable material for the fabrication of advanced sensing devices.
Authors: Kaori Nishizawa, Takeshi Miki, Eiji Watanabe, Hiroshi Taoda
Abstract: Two types of titanium dioxide sol solutions were prepared using titanium tetra-isopropoxide, urea, 2-methoxyethanol and water. The prepared sol solutions were dip-coated onto fused silica plates. These as-prepared films were dried at 100 °C and then annealed at 650 °C. The annealed films were anatase type titanium dioxides. Visible light absorption by the films was observed in wavelengths longer than 400 nm. Also, photodegradation of methylene blue by visible light irradiation was accelerated in the presence of the films prepared by these methods.
Authors: Kaori Nishizawa, Eiji Watanabe, Masaki Maeda
Abstract: Titanium dioxide sol solution was prepared using titanium tetra-isopropoxide, urea, 2-methoxyethanol. After that, ultraviolet light was irradiated to the sol solution, then, H2O was added to the solution. The prepared sol solution was dip-coated onto fused silica plates. The as-prepared films were dried at 100 °C and then annealed at 650 °C. The annealed films were anatase type titanium dioxides. Visible light absorption by the films was observed in wavelengths longer than 380 nm. Also, photodegradation of methylene blue by visible light irradiation was accelerated in the presence of the films prepared by these methods.
Authors: Jia Cai Kuang, Da Xiang Yang, Jian Feng, Chang Rui Zhang
Authors: K. Prem Ananth, Sujin P. Jose, A. Joseph Nathanael, Tae Hwan Oh, D. Mangalaraj, A.M. Ballamurugan
Abstract: Silica nanotubes with controlled diameter and length were synthesised by using a novel and modified template-sol-gel method. The consistency and order of silica nanotubes mainly depend on the anodic alumina membrane (AAO) template that was used during the preparation process. The AAO membrane was chemical etched using different concentrations (5, 7 and 10 wt %) of phosphoric acid. The obtained silica nanotubes had diameters in the range of 220-280 nm and thicknesses around 70-90 nm as observed by field emission scanning electron microscopy (FE-SEM). Scanning transmission electron microscopy (STEM) images enable us to view the arrangement of the hollow cylindrical silica nanotubes. Porosity of the silica nanotubes was investigated by nitrogen adsorption-desorption. The mesoporous silica nanotubes show characteristic type IV isotherm behaviour, with double capillary condensation step in the relative pressure range of 0.2-1.0 (p/p0). Thermogravimetric (TGA) and differential thermal (DTA) analyses confirm the thermal stability of the silica nanotubes and their weight changes and endo and exothermic reactions. The structural and functional group analyses of the silica nanotubes were carried out by using X-ray diffraction (XRD) patterns and Fourier transform infrared spectroscopy (FT-IR).
Authors: Pawel Popielarski, Waclaw Bala, Kazimierz Paprocki
Abstract: In this work, the dielectric response of ZnO thin films has been studied over a temperature range of 200 K - 550 K. The dielectric response of polycrystalline ZnO thin films in the frequency domain was measured from 42 Hz - to 5 MHz with a small AC signal amplitude at different temperatures. Influence of the light on conductivity has been also investigated. A universal power law relation was brought into picture to explain the frequency dependence of AC conductivity. The temperature dependence of AC conductivity was analyzed in detail. The activation energy obtained from the temperature dependence of AC conductivity was attributed to the shallow trap-controlled space charge conduction in the bulk of the sample.
Authors: Xanthippi Chatzistavrou, Konstantinos M. Paraskevopoulos, Vehid Salih, Aldo Roberto Boccaccini, Toshihiro Kasuga
Abstract: The aim of this work was to improve a newly developed family of glass-ceramic composite materials by incorporating silver ions in the ceramic structure, thus developing new Ag-doped materials with the ability of showing antibacterial activity for dental applications. Two different sol-gel methodologies were applied for the fabrication of colorless, homogenous and chemically durable materials which can slowly release silver ion for relatively long periods. Both methods led to the successful development of Ag-doped glass-ceramics with silver ions incorporated in the structure that can slowly release in buffer solution, during a period of 45 days. The potential, application of these materials involve the development of bioactive surfaces on dental substrates which can seal the marginal gap creating a bacterial free environment finally supporting the success of dental restorations.
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