A Direct Route to Active Silica Nanoparticles

2007 ◽  
Vol 121-123 ◽  
pp. 65-68
Author(s):  
X.Q. Chen ◽  
Y.Y. Liu ◽  
K.H. Qi ◽  
X. Zhou ◽  
J.H. Xin
Keyword(s):  
Aqueous Solution ◽  
Silica Nanoparticles ◽  
Sol Gel ◽  
Silica Particles ◽  
Second Step ◽  
Gel Method ◽  
Direct Route ◽  
Monodisperse Silica ◽  
Acidic Conditions ◽  
Hydrolysis Of

Monodisperse silica particles containing available active C=C bonds were directly prepared by a simple two-step sol-gel method. In the first step the hydrolysis of vinyltrimethoxysilane (VTMS) was performed under acidic conditions in an aqueous solution. In the second step the condensation of the siloxane precursors progressed under basic conditions, resulting in production of silica nanoparticles containing available active C=C bonds. The products were characterized using SEM and FTIR.

Pore size control of monodisperse silica particles by dual template sol–gel method

2019 ◽  
Vol 94 (1) ◽  
pp. 186-194
Author(s):  
Qiuhua Wang ◽  
Huiying Wang ◽  
Yaling Wu ◽  
Lingping Cheng ◽  
Lunan Zhu ◽  
...  
Keyword(s):  
Pore Size ◽  
Sol Gel ◽  
Size Control ◽  
Silica Particles ◽  
Gel Method ◽  
Sol Gel Method ◽  
Monodisperse Silica ◽  
Pore Size Control

scholarly journals Effect of various amount of ammonium hydroxide on morphology of silica nanoparticles grown by sol-gel

2018 ◽  
Vol 14 ◽  
pp. 482-484
Author(s):  
Farah Shahirah Norazmi ◽  
Kashif Tufail Chaudhary ◽  
Elham Mazalan ◽  
Zuhaib Hader ◽  
Jalil Ali
Keyword(s):  
Silica Nanoparticles ◽  
Sol Gel ◽  
Ammonium Hydroxide ◽  
Ammonia Solution ◽  
Tetraethyl Orthosilicate ◽  
Ammonium Hydroxide Solution ◽  
Monodisperse Silica ◽  
Cell Coating ◽  
Hydrolysis Of

Silica nanoparticles have drawn significant intentions for their potential in solar cell coating applications. These products occupy a noticeable position in a scientific research because of their easy preparation and wide uses for different technological applications. The quality of silica nanoparticles are highly dependent on the size. This study reports the synthesis of monodisperse silica nanoparticles by hydrolysis of tetraethyl orthosilicate (TEOS) in a mixture of ethanol and DI water as a solvent and ammonium hydroxide solution (NH4OH) as a catalyst. The solutions are stirred overnight and dried in a low-pressure furnace under 100 mbar for 3 hours at 60°C. Various-sized silica nanoparticles in the range 80 nm – 250 nm were examined under field emission scanning electron microscopy (FESEM). With the increasing volume of ammonia solution, an increase in the size of silica nanoparticles were observed. 

Performance of Polishing Slurries containing Silica Particles grown by Sol-Gel Method

2000 ◽  
Vol 613 ◽  
Author(s):  
Sun Hyuk Bae ◽  
Jae-Hyun So ◽  
Seung-Man Yang ◽  
Do Hyun Kim
Keyword(s):  
Fumed Silica ◽  
Sol Gel ◽  
Particle Growth ◽  
Silica Particles ◽  
Gel Method ◽  
Sol Gel Method ◽  
Irregular Shapes ◽  
Wafer Polishing ◽  
Transmission Electron ◽  
Silica Slurry

ABSTRACTSilica slurry used as abrasives in wafer polishing process is made by dispersing silica particles in an alkali solution. Since commercially available colloidal or fumed silica particles need some modifications to be directly used as abrasive slurry due to their small sizes, irregular shapes or broad size distribution, we have prepared silica abrasives by particle growth of fumed silica or colloidal silica as seeds by sol-gel method. Silica slurries prepared by this step-wise growth from commercial seeds were tested using one-armed polisher for the comparison with commercial slurries and showed the performance comparable to commercial slurries. Microstructures of polishing slurries were investigated using transmission electron microscopy and ARES rheometer. From the result, stability of the slurry was found to be more important than the primary particle sizes for the polishing performance.

Effect of acidity on the properties of silica-aluminas synthesized by sol-gel method

2020 ◽  
Vol 63 (7) ◽  
pp. 126-132
Author(s):  
Lyubov V. Furda ◽  
◽  
Evgenia A. Tarasenko ◽  
Sofya N. Dudina ◽  
Olga E. Lebedeva ◽  
...  
Keyword(s):  
Surface Area ◽  
Sol Gel ◽  
Molar Ratio ◽  
Active Centers ◽  
Indicator Method ◽  
Synthesis Conditions ◽  
Alkaline Conditions ◽  
Acidic Conditions ◽  
Amphoteric Properties ◽  
Hydrolysis Of

In the present work amorphous silica-aluminas were synthesized by the coprecipitation method during the hydrolysis of an alcohol solution of tetraethoxysilane (with a tetraethoxysilane: alcohol mass ratio of 1: 1) and 6% aqueous solution of aluminum nitrate at pH values of 1, 3, and 10. The Si/Al molar ratio for all synthesized samples were 4.72 (± 0.29). The amorphous character of the investigated materials was confirmed by X-ray phase analysis. According to the results of scanning electron microscopy, it was found that the resulting powders have particles with a size of 1-20 μm. It was shown that the conditions of synthesis affected the specific surface area and porosity of the materials under study. By the method of low-temperature adsorption-thermodesorption of nitrogen it was established that silica-aluminas obtained under acidic conditions were microporous materials. For the sample obtained under alkaline conditions (pH = 10), the contribution of macropores is very significant. A decrease in surface area is observed as the pH of the synthesis increases. The Hammett indicator method was used to identify and quantify surface centers of different acidity. All studied silica-aluminas are characterized by the presence of both Brønsted basic (pKax from 7 to 12.8) and acidic (pKax from 0 to 7) centers, and Lewis basic (pKax from -4.4 to 0) with a pronounced maximum at pKax = 1.02. It was found that the synthesis conditions had a significant effect on the concentration of active centers. The values of the Hammett function are practically the same for the 3 studied silica-aluminas and describe the studied samples as materials of medium acidity. The variety of Lewis and Brønsted centers on the surface indicates the amphoteric properties of the materials under study. This gives the samples the properties of polyfunctional sorbents and catalysts.

The Influence of Water Content on the Growth of the Hybrid-Silica Particles by Sol-Gel Method

Silicon ◽  
2020 ◽  
Author(s):  
Xijia Zhao ◽  
Yihan Wang ◽  
Jianhui Luo ◽  
Pingmei Wang ◽  
Peiwen Xiao ◽  
...  
Keyword(s):  
Water Content ◽  
Sol Gel ◽  
Silica Particles ◽  
Gel Method ◽  
Sol Gel Method ◽  
Hybrid Silica ◽  
Influence Of Water

Preparation and Performance of Porous Membrane Materials Using the Sol-Gel Method

2010 ◽  
Vol 33 ◽  
pp. 251-253
Author(s):  
Peng Zhang ◽  
Gang Chen ◽  
Bin Guo ◽  
Shu Kang Cheng
Keyword(s):  
Sol Gel ◽  
Porous Membrane ◽  
Silica Particles ◽  
High Tech ◽  
Experimental Conditions ◽  
Preparation Methods ◽  
Gel Method ◽  
Membrane Materials ◽  
Sol Gel Method ◽  
And Performance

Porous membrane materials have the universal use, so it is widely considered as one of the most promising high-tech. Different membranes have different preparation methods. In this paper, the sol-gel method was applied to prepare silica particles using ammonia as catalyst of TEOS hydrolysis, then silica particles were mixed with polyethylene, and finally silica particles were dissolved with hydrofluoric acid, leaving holes, the porous materials were obtained. The results show that: (1) In this experimental conditions, the size of silica particles are closely related to the water content of the system. (2) The size of silica particles affects the agglomeration of particles. The size of silica particles are smaller, the agglomeration is more obvious. (3) As the content of PE increases, the porosity of the samples decreases continuously; in theory, when the content of silica is low, the hole will be greater.

Properties of anion exchange membrane based on polyamine: Effect of functionalized silica particles prepared by sol–gel method

2018 ◽  
Vol 322 ◽  
pp. 85-92 ◽  
Author(s):  
Narges Ataollahi ◽  
Elisa Cappelletto ◽  
Keti Vezzù ◽  
Vito Di Noto ◽  
Gianni Cavinato ◽  
...  
Keyword(s):  
Anion Exchange ◽  
Sol Gel ◽  
Silica Particles ◽  
Anion Exchange Membrane ◽  
Functionalized Silica ◽  
Gel Method ◽  
Sol Gel Method ◽  
Exchange Membrane
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