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Sol-Gel Preparation of Thick TiO<sub>2</sub> Films for Structural Coloration
摘要： We studied sol-gel processing of thick and crack-free TiO2 films to synthesize structural color materials. The viscosity of the alkoxide-based precursor sols was stabilized by the addition of acetyl acetone, which improved control of the spin coating thickness. We used a TiO2/SiO2/TiO2 triple-layer structure and second-order reflection conditions to produce structural coloration. This design yielded a sharp spectral peak and bright coloration; however, a TiO2 layer with a thickness greater than 200 nm was required, which is much thicker than that required for the first-order of reflection. Crack formation in the thick films was suppressed by the addition of ethyl cellulose to the precursor sols. As a consequence, color-tuned TiO2/SiO2/TiO2 films were successfully prepared and exhibited various bright colors in the visible light wavelength range, including two primary colors of light, namely blue and green. Green coloration from flake-shaped particles was also demonstrated.
关键词： TiO2,structural color,crack formation,flake-like powders,sol-gel method
更新于2025-09-23 15:22:29
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Epitaxial Growth of Orthorhombic GaFeO3 Thin Films on SrTiO3 (111) Substrates by Simple Sol-Gel Method
摘要： A Sol-gel method assisted with spin-coating has been successfully used to grow orthorhombic GaFeO3 epitaxial films on SrTiO3 (111) substrates for the first time. The film with Pna21 crystal structure has been grown along the c-axis. The rocking curve of (004) reflection shows that the Full-Width at Half-Maximum (FWHM) value could be determined to be 0.230°, indicating good single crystallinity and high quality. X-ray Φ scan reveals a three-fold symmetry of the substrate and a six-fold symmetry of the film, respectively. The in-plane domains rotate 60° from each other in the film. Uniform film with dense structure, columnar grains with similar grain size was obtained. The thickness of the film was evaluated to be ~170 nm. The roughness value (RMS) measured by AFM was 4.5 nm, revealing a flat film. The in-plane Magnetization versus Magnetic field (M-H) curve at 5 K performs a typical ferri- or ferromagnetic hysteresis loop with a saturated magnetization (Ms) value of 136 emu/cm3. The Curie temperature could be determined to be 174 K. Compared to Pulsed Laser Deposition (PLD), the sol-gel method can prepare large area films with low cost. These new films show promising applications in multiferroic devices.
关键词： GaFeO3 film,magnetic property,sol-gel method,multi-domain structure,epitaxial growth
更新于2025-09-23 15:22:29
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Polyacrylamide gel synthesis and photocatalytic performance of PbBiO2Br nanosheets
摘要： We designed and fabricated novel PbBiO2Br nanosheets via Polyacrylamide gel method. XRD, XPS, SEM, TEM and UV-vis absorption spectra were used to investigate the crystal microstructure, morphology, band-gap and optical properties of the as-prepared PbBiO2Br nanosheets. The photocatalytic performance and stability of PbBiO2Br nanosheets were evaluated by removing methylene blue (MB) aqueous solution (20 mg/L) under visible-light irradiation. Results showed that the PbBiO2Br was brick-like nanosheets with an average side size of about 80 nm and the absorption edge at about 500 nm, and exhibited an excellent photocatalytic performance under visible light irradiation. Moreover, the repeated cycle experimental results demonstrated that the PbBiO2Br nanosheets had a good chemical stability. Finally, the possible photocatalytic mechanism was proposed and discussed.
关键词： Semiconductor,PbBiO2Br,Polymers,Polyacrylamide gel,Photocatalysis
更新于2025-09-23 15:22:29
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[ACS Symposium Series] Gels and Other Soft Amorphous Solids Volume 1296 || Probe Diffusion Dynamic Light Scattering of Polymer solutions and Gels
摘要： Probe diffusion dynamic light scattering technique is a powerful to investigate the dynamics of polymer chains in polymer solutions and gels. Not only the local dynamics and/or local viscosity but also the gel point and the post-gel dynamics can be investigated. In this chapter, we discuss (1) a conventional probe diffusion of radical polymerization of poly(N-isopropylacrylamide) (PNIPAM) aqueous system, (2) an in-situ isorefractive probe diffusion of tetra-arm poly(ethylene glycol) (Tetra-PEG) undergoing sol-gel transition via cross-end-coupling, and (3) of PNIPAM radical polymerization. It is demonstrated that the gel point is determined as a function of the reaction conversion, which is a more universal measure than the reaction time. The post-gel dynamics explored by the probe particles illuminates the local dynamics in a “pool” of the sol phase surrounded by a gel network. Furthermore, comparison in dynamics is made between well-controlled uniform networks (Tetra-PEG gels) and randomly cross-linked more heterogeneous networks (PNIPAM gels) the probe size from the viewpoints of dependence and scattering angle dependence.
关键词： gel point,Tetra-PEG,post-gel dynamics,Probe diffusion,PNIPAM,gels,polymer solutions,dynamic light scattering
更新于2025-09-23 15:21:21
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Sol-gel coating of colloidal particles deposited glass surface pertinent to self-cleaning applications
摘要： A sol-gel coating using colloidal silica on a glass surface is carried out towards improving the self-cleaning properties. The optical transmittance and hydrophobic characteristics of the resulting coating are analyzed using analytical tools. Since the sol-gel coating reduces the optical transmittance of the glass samples, due to scattering and diffusion of the incident optical radiation at the coating surface, silicon oil (Sigma-Aldrich, 10 cSt) impregnation method is introduced to improve the optical transmittance. Silicon oil has good heat transfer characteristics, stable properties over range of temperatures, and optically transparent characteristics with refractive index of 1.4034. The resulting coated surface is tested in outdoor environments to examine the dust effect on the optical transmittance of the sol-gel coated and oil impregnated glass samples. It is found that deposition of 75 nm size silica particles on the glass surface modifies the texture height of the sol-gel coating, which in turn, improves the surface hydrophobicity. Sol-gel coating results in a web-type fully connected porous structures; in which case, agglomeration of the synthesized particles is responsible for the fully connected porous texture at the coating surface. The optical transmittance remains low for the sol-gel coated glass samples because of scattering and diffusion of the incident optical radiation at the coating surface. Silicon oil impregnation improves the optical transmittance of the sol-gel coated samples. The dust particles immerse into the oil film and reduce the optical transmittance of the oil impregnated samples in outdoor environments.
关键词： Sol-gel coating,Hydrophobicity,Silicon oil impregnation,Silica,Outdoor testing
更新于2025-09-23 15:21:21
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[IEEE 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - Shanghai, China (2018.8.8-2018.8.11)] 2018 19th International Conference on Electronic Packaging Technology (ICEPT) - The characters of WO<inf>3</inf> electrochromic film prepared by sol-gel method
摘要： Electrochromic device is made up of transparent conduction layer, electrochromic layer, electrolyte layer and counter electrode layer. In this paper, we used a sol-gel method, which could decrease the cost, to prepare the WO3 electrochromic film. We firstly spin-coated the precursor on the ITO glass and then annealed the WO3 film at different temperature. Finally, we covered the electrolyte layer on the WO3 film and assembled it into electrochromic device. The film was investigated by Scanning electron microscope (SEM), X-ray diffraction (XRD) and UV spectrophotometer. We found the precursor’s color will change from yellow to white after it was stirred over 4h. After comparison, the film annealed at 573K could get the highest contrast ratio.
关键词： Electrochromic Film,Sol-gel method,Tungsten trioxide
更新于2025-09-23 15:21:21
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Double Notched Long-Period Fiber Grating Characterization for CO2 Gas Sensing Applications ?
摘要： In this study, we applied a double-sided inductively coupled plasma (ICP) process to nanostructure long-period fiber grating (LPFG) in order to fabricate a double-notched LPFG (DNLPFG) sensor with a double-sided surface corrugated periodic grating. Using the sol-gel method, we also added thymol blue and ZnO to form a gas sensing layer, thus producing a DNLPFG CO2 gas sensor. The resulting sensor is the first double-sided etching sensor used to measure CO2. The experimental results showed that as the CO2 concentration increased, the transmission loss increased, and that the smaller the fiber diameter, the greater the sensitivity and the greater the change in transmission loss. When the diameter of the fiber was 32 μm (and the period was 570 μm) and the perfusion rate of CO2 gas was 15%, the maximum loss variation of up to 3.881 dB was achieved, while the sensitivity was 0.2146 dB/% and the linearity was 0.992. These results demonstrate that the DNLPG CO2 gas sensor is highly sensitive.
关键词： sol-gel,CO2,gas sensor
更新于2025-09-23 15:21:21
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A dosimetric study on the use of 3D-printed customized boluses in photon therapy: A hydrogel and silica gel study
摘要： Purpose: The aim of the study was to compare the dose differences between two kinds of materials (silica gel and hydrogel) used to prepare boluses based on three‐dimensional (3D) printing technologies and commercial bolus in head phantoms simulating nose, ear, and parotid gland radiotherapy. Methods and materials: We used 3D printing technology to make silica gel and hydrogel boluses. To evaluate the clinical feasibility, intensity modulated radiation therapy (IMRT) plans were created for head phantoms that were bolus‐free or had a commercial bolus, a silica gel bolus, or a hydrogel bolus. Dosimetry differences were compared in simulating nose, ear, and parotid gland radiotherapy separately. Results: The air gaps were smaller in the silica gel and hydrogel bolus than the commercial one. In nose plans, it was shown that the V95% (relative volume that is covered by at least 95% of the prescription dose) of the silica gel (99.86%) and hydrogel (99.95%) bolus were better than the commercial one (98.39%) and bolus‐free (87.52%). Similarly, the homogeneity index (HI) and conformity index (CI) of the silica gel (0.06; 0.79) and hydrogel (0.058; 0.80) bolus were better than the commercial one (0.094; 0.72) and bolus‐free (0.59; 0.53). The parameters of results (HI, CI, V95%) were also better in 3D printing boluses than in the commercial bolus or without bolus in ear and parotid plans. Conclusions: Silica gel and hydrogel boluses were not only good for fit and a high level of comfort and repeatability, but also had better parameters in IMRT plans. They could replace the commercial bolus for clinical use.
关键词： hydrogel,silica gel,radiotherapy,tissue compensator,3D printing
更新于2025-09-23 15:21:21
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Visible Light Driven Mesoporous Mn and S Co-doped TiO2 Nano material: characterization and Applications in Photocatalytic Degradation of Indigocarmine dye and Antibacterial Activity
摘要： The present study explored the Photocatalytic & antibacterial activity of Mesoporous Mn and S co-doped TiO2 nano material synthesized by sol-gel method. As prepared samples were characterized by X-ray diffraction (XRD), X-ray photo electron spectroscopy(XPS), Scanning electron microscopy (SEM), Energy dispersive X-ray Spectroscopy(EDX), Fourier transform infrared spectroscopy(FT-IR), UV-Visible Diffused Reflectance Spectroscopy(UV-Vis-DRS),Transmission electron Microscopy(TEM), Brunauer-Emmett-Teller (BET) and Photoluminescence (PL).The Characterization results revealed that all the co-doped and undoped samples shows anatase phase. The Frequency shift of Ti-O-Ti in the catalyst samples was observed in FT-IR due to substitutional doping of Mn and S by replacing Ti and O, Further the catalyst shows smooth spherically shaped small particle size (7.6 nm) with high surface area (155.87 m2/g) and having less band gap energy (2.58 eV). The most reactive ?OH are produced during the progress of reaction was determined by using Photo luminescence (PL) technique. The photocatalytic efficiency and antibacterial activity was evaluated by degradation of Indigo carmine(IC), Bacillus coagulans and klebsiella pneumonia respectively. The complete degradation of IC was achieved at optimum reaction parameters such as 0.150g of the catalyst dosage, solution pH=4 and initial dye concentration 20ppm with the catalyst of 1.0Wt% of Mn-0.25Wt% of S co-doped Titania with in 90 min. The zone of inhibition bacterial growth was observed (24mm and 23mm) compared to control value (Chloramphenicol) 25mm and 24mm.
关键词： antibacterial activity,Mn-S,TiO2,Indigo carmine,Photocatalytic activity,Sol-gel method
更新于2025-09-23 15:21:21
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Cyanide degradation in aqueous solution by heterogeneous photocatalysis using boron-doped zinc oxide
摘要： The photocatalytic activity of boron-doped ZnO with varying concentration (1, 1.5 and 2% wt of B) synthesized by sol-gel method was evaluated on cyanide (CN-) degradation in aqueous solution under simulated solar radiation. The obtained catalysts were characterized by XRD, UV-Vis/DRS, ICP-OES, FT-IR, and XPS. The photocatalytic experiments were carried out in a quartz batch reactor using 300 mL of cyanide solution adjusted at pH 11, evaluating different parameters such as the amount of B dopant, catalyst loading and initial concentration of cyanide solution. A 23 central composite faced design was used to maximize CN- photocatalytic degradation. The cyanide concentration was measured by ISE potentiometric method and the content of intermediate ions (OCN?, NO3?, and NH4+) was determined by UV-visible spectrophotometry. The boron incorporation into ZnO lattice (ZnO-B) reduced wurtzite crystallite size (25 nm) and narrowed band gap (3.0 eV) compared to bare ZnO (43 nm and 3.2 eV, respectively). The ZnO-B 1.5 wt% showed better photocatalytic performance by degrading 89% of a 10 mg L-1 CN- solution compared to 75% that was reached by undoped ZnO; using in both cases 1.4 g L-1 of catalyst loading at accumulated energy of 400 kJ m-2.
关键词： central composite faced design,ZnO-B,sol-gel,cyanate,cyanide
更新于2025-09-23 15:21:21