scholarly journals Sol-Gel Film Formation by Dip Coating

1990 ◽  
Vol 180 ◽  
Author(s):  
Alan J. Hurd ◽  
C. Jeffrey Brinker
Keyword(s):  
Film Formation ◽  
Sol Gel ◽  
Dip Coating ◽  
Point Of View ◽  
Inverse Form ◽  
Capillary Phenomena ◽  
Gel Film ◽  
Capillary Collapse ◽  
Field Singularity ◽  
Film Profile

ABSTRACTThe physical aspects of sol-gel film formation are discussed, including the steady state film profile during dip coating, evaporation, and capillary phenomena. It is argued that, since the evaporation rate increases singularly near a sharp boundary (analogous to an electric field singularity near a sharp conductor), the film profile near the drying line falls off precipitously, following the inverse form of the evaporation singularity. Finally, the large tensile pressures in the solvent during the final stage of drying of a porous film are discussed from the point of view of controlling the degree of capillary collapse.

scholarly journals Synthesis and Characterization of TiO2/SiO2 Monoliths as Photocatalysts on Methanol Oxidation

2018 ◽  
Vol 2018 ◽  
pp. 1-8 ◽  
Author(s):  
Rigoberto Regalado-Raya ◽  
Rubí Romero-Romero ◽  
Osmín Avilés-García ◽  
Jaime Espino-Valencia
Keyword(s):  
Thin Film ◽  
Methanol Oxidation ◽  
Immersion Time ◽  
Film Formation ◽  
Anatase Phase ◽  
Sol Gel ◽  
Packed Bed ◽  
Dip Coating ◽  
Packed Bed Reactor ◽  
Titanium Butoxide

Photocatalytic materials based on silica-titania (SiO2-TiO2) were synthesized by sol-gel and dip-coating method. TEOS and titanium butoxide were used as precursors of the silica-titania, respectively. A thin film with anatase phase was obtained on the surface of the support. The effect of variables as dispersion mechanism, immersion time, and number of treatment cycles were studied. The materials were characterized using X-ray diffraction, scanning electron microscopy, energy dispersion scanning, and N2 adsorption-desorption. The highest crystallinity of TiO2 on silica, high specific surface area in TiO2-SiO2 materials, and thin film formation were obtained by using a stirring plate and minimum immersion time. The so synthesized catalyst allowed the production of formaldehyde from the photocatalyzed methanol oxidation in a packed-bed reactor.

Changes of thickness and refractive index of silica sol-gel film by dip coating process

2014 ◽  
Vol 26 (7) ◽  
pp. 72005
Author(s):  
张日东 Zhang Ridong ◽  
严鸿维 Yan Hongwei ◽  
吕海兵 Lü Haibing ◽  
张尽力 Zhang Jinli ◽  
晏良宏 Yan Lianghong ◽  
...  
Keyword(s):  
Refractive Index ◽  
Sol Gel ◽  
Dip Coating ◽  
Silica Sol ◽  
Coating Process ◽  
Gel Film

The Influencing Factors for the Thickness of Silica Sol-Gel Film by the Dip Coating Process

2014 ◽  
Vol 597 ◽  
pp. 165-169
Author(s):  
Jie Hong Lei ◽  
Ri Dong Zhang
Keyword(s):  
Thin Films ◽  
Surface Roughness ◽  
Refractive Index ◽  
Sol Gel ◽  
Dip Coating ◽  
Silica Sol ◽  
Coating Process ◽  
Power Functions ◽  
Withdrawal Speed ◽  
Gel Film

The porous sol-gel silica thin films were prepared on silicon substrate by the dip coating process. The surface roughness and microstructure of the film was measured by optical microscopy and AFM .Coating thickness and refractive index were measured by ellipsometry method. Influence of withdrawal speed and concentration of colloid was investigated for the thickness of silica. The relation of the thickness and withdrawal speed was fitted by the linear and power functions, and the results were analyzed and compared. It was found that the films with the same thickness prepared by different concentrations of colloid have different refractive indexes. The experimental results indicated that the thickness and refractive index of the film can be controlled by changing the withdrawal speed and colloid concentration.

scholarly journals On the Use of a TiO2 Sol-Gel for Horseradish Peroxidase Enzyme Immobilization for Development of an Amperometric Biosensor

2021 ◽  
Author(s):  
Carolina da Rocha ◽  
Carolina Uliana ◽  
Hideko Yamanaka
Keyword(s):  
Horseradish Peroxidase ◽  
Sol Gel ◽  
Pharmaceutical Formulations ◽  
Dip Coating ◽  
Pencil Graphite Electrode ◽  
Aminosalicylic Acid ◽  
Electron Mediator ◽  
Tio2 Sol ◽  
Gel Film ◽  
Peroxidase Enzyme

The sol-gel technique has drawn considerable attention in the area of biomolecules immobilization by virtue of its intrinsic properties including chemical inertness, thermal stability, and good biocompatibility. The present work reports the development of a bio-sensing methodology which involves the immobilization of horseradish peroxidase enzyme (HRP) on pencil graphite electrode (PGE) using TiO2 sol-gel and its application for 5-aminosalicylic acid (5-ASA) determination in pharmaceutical formulations. TiO2 sol-gel film was deposited on the PGE surface by dip coating, and the HRP enzyme was immobilized on the film by adsorption and cross-linked binding using glutaraldehyde. The analytical performance of the methodology was investigated through amperometric measurements at –0.08 V in the presence of 5-ASA (electron mediator) and hydrogen peroxide (substrate). The biosensor was successfully applied for 5-ASA determination, where limits of detection and quantification of 3.3 and 10.0 μmol L-1, respectively, were obtained. The application of the methodology for 5-ASA determination in pharmaceutical formulations led to satisfactory recovery rates ranging from 80 to 98%. The biosensor developed in this work is simple, inexpensive and has the potential to be applied for the determination of other pharmaceutical compounds, which also act as electron mediators in the catalytic cycle of HRP.

Modification of Electroless Nickel-Plating Coatings with Sol-Gel Film

2005 ◽  
Vol 475-479 ◽  
pp. 3835-3838 ◽  
Author(s):  
Hui Cong Liu ◽  
Liqun Zhu ◽  
Yan Bin Du
Keyword(s):  
Heat Treatment ◽  
Oxidation Resistance ◽  
Sol Gel ◽  
Electroless Nickel ◽  
Dip Coating ◽  
Treatment Temperature ◽  
Gel Film ◽  
Sol Gel Films ◽  
Corrosion And Oxidation

Four Sol-Gel films were developed by dip-coating electroless nickel-plated samples in different Sols, followed by heat treatment. The effects of the coating times and heat treatment temperature on the corrosion, oxidation resistance and wearing quality of the modified coating were examined. Results show that, after six coating, Sol-Gel films obtained can provide good corrosion and oxidation resistance, and their anti-corrosion quality remains high even after being oxidized at 500 °C for 60 hours. Addition of inorganic molybdenum salt or chromate into the Ti Sol also makes the wearing quality of the Sol-Gel film better.

Spectral hole burning in sol-gel-derived Eu3+-doped film

2000 ◽  
Vol 15 (5) ◽  
pp. 1190-1194 ◽  
Author(s):  
Masayuki Nogami ◽  
Tomotaka Ishikawa ◽  
Tomokatsu Hayakawa ◽  
Tomokatsu Hayakawa
Keyword(s):  
Sol Gel ◽  
Dip Coating ◽  
Treatment Temperature ◽  
Hole Burning ◽  
Spectral Hole Burning ◽  
Spectral Hole ◽  
Gel Film ◽  
Total Fluorescence ◽  
Gel Technique ◽  
The Eu

The sol-gel technique was applied to the preparation of Eu3+ ion–doped films, which showed persistent spectral hole burning. A gel film of ∼3500-nm thickness was prepared by dip-coating of the solution synthesized from Si(OC2H5)4, CH3Si(OC2H5)3, Eu(NO3)3 · 6H2O, and hydropropyl-cellulose. The spectral hole was burned in the 7F0 → 5D0 transition band of the Eu3+ ions at 7 K, the depth of which was 24% of the total fluorescence intensity and decreased as the heat-treatment temperature of film increased. It was found that the hole was thermally filled and erased above ∼170 K; the temperature at which the hole was erased was lower for the film heated at high temperature.

scholarly journals Effect of titanium source and sol-gel TiO2 thin film formation parameters on its morphology and photocatalytic activity

2020 ◽  
Vol 0 (0) ◽  
Author(s):  
Piotr Dulian ◽  
Jan Zajic ◽  
Witold Żukowski
Keyword(s):  
Thin Films ◽  
Photocatalytic Activity ◽  
Surface Structure ◽  
Uv Light ◽  
Film Formation ◽  
Sol Gel ◽  
Titanium Isopropoxide ◽  
Dip Coating ◽  
Single Step ◽  
Titanium Butoxide

AbstractTiO2 thin films with different surface structure have been prepared from alkoxide solutions by the sol-gel method using different cationic precursors and heat treatment techniques. The effect of using titanium isopropoxide as well as titanium butoxide as a titanium source on the surface structure and photocatalytic activity of the resultant thin films was studied. Significant differences in the rate of hydrolysis and condensation reactions during the sol-gel synthesis were observed for these titanium precursors. This had a direct influence on the morphology of the as-prepared TiO2 films. Higher quality oxide coatings were obtained from titanium isopropoxide. They were characterized by a smaller grain size, improved surface roughness and uniform coverage of the glass substrate. A beneficial effect of calcination process after each sol application cycle in contrast to single step calcination after all dip-coating cycles was observed. Photocatalytic degradation tests showed that methyl orange was decolorized in the presence of all prepared TiO2 films by exposing their aqueous solutions to UV light (λ = 254 nm). The highest photocatalytic activity had the TiO2 layer produced using titanium isopropoxide.

scholarly journals The Study of Graphene Oxide on the Regulations and Controls of the Sol-Gel Film Structure and Its Performance

Metals ◽  
2021 ◽  
Vol 12 (1) ◽  
pp. 20
Author(s):  
Yan Gao ◽  
Yadong Fan ◽  
Junxi Zhang ◽  
Xuanxuan Liu ◽  
Ning Wang ◽  
...  
Keyword(s):  
Graphene Oxide ◽  
Film Formation ◽  
Sol Gel ◽  
Corrosion Current ◽  
Film Structure ◽  
Regulation Mechanism ◽  
Coating Films ◽  
Gel Film ◽  
Diffusion Paths ◽  
Protection Capability

A facile strategy to boost anticorrosion potency of graphene oxide/silica hybrid sol-gel coating is developed through fully exploiting the capabilities of graphene oxide (GO). Together with a barrier to corrosives and crack inhibitor, GO was further explored herein as a regulator to regulate the gelation process and provide robust coating films with stratified microstructures and ultimately extended diffusion paths. The sol-gel coating with stratified microstructure achieved on AA5052 aluminum alloy surface afforded greatly enhanced corrosion protection capability as assessed by electrochemical measurements and immersion tests. The corrosion current density of the sample of a hybrid GO sol-gel film was about 30 times less than that of sample of pure sol-gel film sample. The regulation mechanism of GO during the film formation process and the anticorrosive protection properties of the film were discussed.

Influence of Surface Finishing on Corrosion Behaviour of Mg-Al Hydrotalcite Doped Hybrid Sol-Gel Coatings on Al Alloy in Saline Environment

2010 ◽  
Vol 636-637 ◽  
pp. 1004-1010 ◽  
Author(s):  
D. Álvarez ◽  
A. Collazo ◽  
Miguel Hernández ◽  
Xosé R. Nóvoa ◽  
C. Pérez
Keyword(s):  
Electrochemical Impedance ◽  
Corrosion Behaviour ◽  
Sol Gel ◽  
Barrier Properties ◽  
Dip Coating ◽  
Surface Finishing ◽  
Al Alloy ◽  
Gel Film ◽  
Aa 2024 ◽  
Surface Morphologies

The behaviour of hybrid sol-gel coatings doped with hydrotalcite-like compound applied on AA2024-T3 alloy was investigated in the present work. The hybrid sol-gel coatings were prepared by copolymerization of 3-Glycydoxypropyltrimethoxysilane (GPTMS) and tetra-n-propoxyzirconium (TPOZ). Three different surface finishing on the aluminium alloy AA-2024-T3, grounded, chemical etching and degreased were studied. A sol-gel film with hydrotalcite 5% w/w was deposited by dip coating procedure. The presence of hydrotalcite particles was confirmed by means of X-ray diffraction technique. The different surface morphologies were characterised using mechanical profilometry. The corrosion resistance properties were studied by means of electrochemical impedance spectroscopy and salt fog spray cabinet. The results show higher barrier properties in grounded aluminium substrates.

scholarly journals Successful Immobilization of Lanthanides Doped TiO2 on Inert Foam for Repeatable Hydrogen Generation from Aqueous Ammonia

Materials ◽  
2020 ◽  
Vol 13 (5) ◽  
pp. 1254
Author(s):  
Miroslava Edelmannová ◽  
Martin Reli ◽  
Lenka Matějová ◽  
Ivana Troppová ◽  
Lada Dubnová ◽  
...  
Keyword(s):  
Hydrogen Generation ◽  
Aqueous Ammonia ◽  
Sol Gel ◽  
Dip Coating ◽  
Ammonia Solution ◽  
Point Of View ◽  
Photocatalytic Hydrogen Generation ◽  
Uva Light ◽  
Coating Method ◽  
Dip Coating Method

We describe the successful possibility of the immobilization of a photocatalyst on foam, which is beneficial from a practical point of view. An immobilized photocatalyst is possible for use in a continuous experiment and can be easily separated from the reactor after the reaction concludes. Parent TiO2, La/TiO2, and Nd/TiO2 photocatalysts (containing 0.1 wt.% of lanthanide) were prepared by the sol-gel method and immobilized on Al2O3/SiO2 foam (VUKOPOR A) by the dip-coating method. The photocatalysts were investigated for the photocatalytic hydrogen generation from an aqueous ammonia solution under UVA light (365 nm). The evolution of hydrogen was compared with photolysis, which was limited to zero. The higher hydrogen generation was observed in the presence of 0.1 wt.% La/TiO2 than in 0.1 wt.% Nd/TiO2. This is, besides other things, related to the higher level of the conduction band, which was observed for 0.1 wt.% La/TiO2. The higher conduction band’s position is more effective for hydrogen production from ammonia decomposition.

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