Ultrahigh Surface Area Nanoporous Silica Particles via an Aero-Sol−Gel Process

Langmuir ◽  
2004 ◽  
Vol 20 (7) ◽  
pp. 2523-2526 ◽  
Author(s):  
S. H. Kim ◽  
B. Y. H. Liu ◽  
M. R. Zachariah
Keyword(s):  
Surface Area ◽  
Sol Gel ◽  
Silica Particles ◽  
Nanoporous Silica ◽  
Sol Gel Process

Microporous Silica Particles Prepared by the Salt-Catalytic Sol-Gel Process with Extremely Low Content of Water

2004 ◽  
Vol 29 (1) ◽  
pp. 19-24 ◽  
Author(s):  
Yasushi Murakami ◽  
Kazuhiko Tanaka ◽  
Yusuke Takechi ◽  
Saki Takahashi ◽  
Yuuki Nakano ◽  
...  
Keyword(s):  
Sol Gel ◽  
Silica Particles ◽  
Microporous Silica ◽  
Sol Gel Process

Texture Evaluation of Sol-Gel Derived Mesoporous Bioactive Glass

2013 ◽  
Vol 284-287 ◽  
pp. 230-234
Author(s):  
Yu Jen Chou ◽  
Chi Jen Shih ◽  
Shao Ju Shih
Keyword(s):  
Surface Area ◽  
Calcination Temperature ◽  
High Surface ◽  
Sol Gel ◽  
High Surface Area ◽  
Nitrogen Adsorption ◽  
Bioactive Glasses ◽  
Transmission Electron ◽  
Sol Gel Process ◽  
Adsorption Desorption

Recent years mesoporous bioactive glasses (MBGs) have become important biomaterials because of their high surface area and the superior bioactivity. Various studies have reported that when MBGs implanted in a human body, hydroxyl apatite layers, constituting the main inorganic components of human bones, will form on the MBG surfaces to increase the bioactivity. Therefore, MBGs have been widely applied in the fields of tissue regeneration and drug delivery. The sol-gel process has replaced the conventional glasses process for MBG synthesis because of the advantages of low contamination, chemical flexibility and lower calcination temperature. In the sol-gel process, several types of surfactants were mixed with MBG precursor solutions to generate micelle structures. Afterwards, these micelles decompose to form porous structures after calcination. Although calcination is significant for contamination, crystalline and surface area in MBG, to the best of the authors’ knowledge, only few systematic studies related to calcination were reported. This study correlated the calcination parameters and the microstructure of MBGs. Microstructure evaluation was characterized by transmission electron microscopy and nitrogen adsorption/desorption. The experimental results show that the surface area and the pore size of MBGs decreased with the increasing of the calcination temperature, and decreased dramatically at 800°C due to the formation of crystalline phases.

Synthesis and formation mechanism of amorphous silica particles via sol–gel process with tetraethylorthosilicate

2019 ◽  
Vol 45 (6) ◽  
pp. 7673-7680 ◽  
Author(s):  
Xianfa Jiang ◽  
Xiaoning Tang ◽  
Lihong Tang ◽  
Bin Zhang ◽  
Huaming Mao
Keyword(s):  
Formation Mechanism ◽  
Amorphous Silica ◽  
Sol Gel ◽  
Silica Particles ◽  
Sol Gel Process

Study on the Dielectric Properties of Hybrid and Porous Polyimide-Silica Films

2008 ◽  
Vol 47-50 ◽  
pp. 973-976 ◽  
Author(s):  
Yi He Zhang ◽  
Qing Song Su ◽  
Li Yu ◽  
Hong Zheng ◽  
Hai Tao Huang ◽  
...  
Keyword(s):  
Dielectric Constant ◽  
Sol Gel ◽  
Silica Particles ◽  
Low Dielectric Constant ◽  
Hybrid Films ◽  
Porous Films ◽  
Silica Films ◽  
Low Dielectric ◽  
Dimethyl Acetamide ◽  
Sol Gel Process

A sol-gel process was used to prepare polyimide-silica hybrid films from the polyimide precursors and TEOS in N,N- dimethyl acetamide, then the hybrid film was treated with hydrofluoric acid to remove the dispersed silica particles, leaving pores with diameters between 80nm to 1µm, depending on the size of silica particles. The structure and dielectric constant of the hybrid and porous films were characterized by FTIR,SEM. The porous films displayed relatively low dielectric constant compared to the hybrid polyimide-silica films.

Preparation and Characterization of Phloroglucinol-Resorcinol-Formaldehyde Carbon Aerogels

2013 ◽  
Vol 423-426 ◽  
pp. 523-527
Author(s):  
Xuan Liu ◽  
Zhen Fa Liu ◽  
Hao Lin Fu ◽  
Rui He ◽  
Li Hui Zhang
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Sol Gel ◽  
High Specific Surface Area ◽  
Carbon Aerogels ◽  
Resorcinol Formaldehyde ◽  
Sol Gel Process ◽  
Solvent Replacement ◽  
Organic Aerogels

Phloroglucinol-resorcinol-formaldehyde organic aerogels (PRF) were prepared using phloroglucinol, resorcinol and formaldehyde in a sol-gel process, solvent replacement and drying at room temperature. The phloroglucinol-resorcinol-formaldehyde carbon aerogels (CPRF) were prepared by charring the PRF at high temperature under the aegis of helium flow. The microstructure of CPRF was characterized by infrared spectroscopy, specific surface area analyzer and scanning electron microscopy. The results showed that the CPRF had continuous network structure and high specific surface area.

Preparation And Characterization Of Ultra-Small Sized Metal And Semiconductor Particles In Sol-Gel Materials

1994 ◽  
Vol 346 ◽  
Author(s):  
Kyung Moon Choi ◽  
Kenneth J. Shea
Keyword(s):  
Pore Size ◽  
Surface Area ◽  
Sol Gel ◽  
High Vacuum ◽  
Particle Sizes ◽  
Transition Metal Clusters ◽  
Surface Areas ◽  
Sol Gel Process ◽  
Bridged Silsesquioxanes

ABSTRACTPoly(l,4-phenylene)-bridged and poly(1,6-hexylene)-bridged silsesquioxanes (PPS and HPS) were prepared by the sol-gel process. The surface areas and pore diameters of these porous xerogels were obtained by BET and BJH methods, respectively. These porous materials were used as a confinement matrix for the growth of small-sized semiconductor and transition metal clusters. Quantum-sized CdS particles in PPS (approximately 58+12 Â) and HPS (91+16 Â) matrices were prepared by first soaking the xerogel in a CdCl2 solution. Following a washing with water, a Na2S solution was then added. EDAX and electron diffraction techniques were used to identify the CdS particles. The particle sizes of CdS in PPS and HPS were determined by both UV measurements and from TEM images. Small-sized Cr clusters were prepared in dried xerogels by an internal doping method. Mixed Cr/CdS phases were also prepared by internal loading of a chromium metal precursor. Following deposition of CdS the xerogel was heated at 120 °C under high vacuum, resulting in formation of intimately mixed phases of Cr metal and CdS. Changes in morphology, in particular the surface area and pore size distribution were noted. A decrease in surface area and an increase in pore size were observed as a result of Cr metal deposition.

Microencapsulation of an acrylate monomer in silica particles by sol–gel process

2010 ◽  
Vol 57 (2) ◽  
pp. 164-171 ◽  
Author(s):  
Cristina Lavinia Nistor ◽  
Dan Donescu ◽  
Alain Perichaud ◽  
Wael Ballout ◽  
Marius Ghiurea
Keyword(s):  
Sol Gel ◽  
Silica Particles ◽  
Acrylate Monomer ◽  
Sol Gel Process

Preparation and Characterization of Ultralow Density Silica Aerogels by Acetonitrile Supercritical Drying

2012 ◽  
Vol 519 ◽  
pp. 83-86 ◽  
Author(s):  
Guang Wu Liu ◽  
Xing Yuan Ni ◽  
Bin Zhou ◽  
Qiu Jie Yu
Keyword(s):  
Specific Surface ◽  
Surface Area ◽  
Specific Surface Area ◽  
Silica Aerogel ◽  
Sol Gel ◽  
Supercritical Drying ◽  
Silica Aerogels ◽  
High Specific Surface Area ◽  
Molar Ratio ◽  
Sol Gel Process

This paper deals with the synthesis of ultralow density silica aerogels using tetramethyl orthosilicate (TMOS) as the precursor via sol-gel process followed by supercritical drying using acetonitrile solvent extraction. Ultralow density silica aerogels with 6 mg/cc of density was made for the molar ratio by this method. The microstructure and morphology of the ultralow density silica aerogels was characterized by the specific surface area, SBET, SEM, and the pore size distribution techniques. The results show that the ultralow density silica aerogel has the high specific surface area of 812m2/g. Thermal conductivities at desired temperatures were analyzed by the transient plane heat source method. Thermal conductivity coefficients of silica aerogel monoliths changed from 0.024 to 0.043W/ (m K) as temperature increased to 400°C, revealed an excellent heat insulation effect during thermal process.

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