Hydrolysis and Condensation of Tetraethyl Orthosilicate at the Air–Aqueous Interface: Implications for Silica Nanoparticle Formation

Author(s):  
Harpreet Kaur ◽  
Shilpi Chaudhary ◽  
Harsharan Kaur ◽  
Monika Chaudhary ◽  
Kailash C. Jena
2014 ◽  
Vol 47 (15) ◽  
pp. 5174-5185 ◽  
Author(s):  
Elena Miloskovska ◽  
Michael Ryan Hansen ◽  
Cornelius Friedrich ◽  
Denka Hristova-Bogaerds ◽  
Martin van Duin ◽  
...  

2011 ◽  
Vol 189-193 ◽  
pp. 4335-4338
Author(s):  
Shi Quan Liu ◽  
Jian Cun Rao ◽  
Hai Xia Wang ◽  
Hui Zhao

Mesoporous silica hollow microspheres were quickly synthesized with a simple reaction medium which only contains tetraethylorthosilicate (TEOS) as silica source, octylamine (OA) as template and water. It is proposed that a dispersion of TEOS-in-water is formed when water is added into the mixture of TOS and OA. Water becomes basic due to dissolution of OA. Fast hydrolysis and condensation of TEOS then occurs at the interface of droplets lead to the formation of silica shells. Hollows are formed due to the volume contraction caused by the large difference in the densities of condensed silica and liquid TEOS. In addition, OA assembles with silica, templating the nanopores in the silica shells.


2014 ◽  
Vol 602-603 ◽  
pp. 63-66 ◽  
Author(s):  
Xue Ye Sui ◽  
Jie Xu ◽  
Chong Hai Wang ◽  
Chang Ling Zhou ◽  
Rui Xiang Liu

A kind of new hollow silica microspheres were proposed in experiment, which are fabricatted by a fast hydrolysis and condensation of tetraethyl orthosilicate taking place around multi-lamellar octylamine vesicles. The morphology of the vesicles is then fixed by a quick gelation process, resulting in hollow organo-silica spheres. After the removal of the template by calcination, nanopores are formed in the hollow shells. The results show that the synthesized hollow silica microspheres have smooth surface and dispersed well£®There are bimodal nanopores in the hollow silica microspheres, with a diameter of 2.1 nm and 0.62nm for the mesopores and micropores respectively, giving a specific surface area of 1123m2/g and a pore volume of 0.6291mL/g£®


2021 ◽  
Vol 18 (1) ◽  
pp. 161
Author(s):  
Nurul Izza Taib ◽  
Famiza Abdul Latif ◽  
Nur Diyana Syazwani Zambri

In this study, this SiO2 has been coated on the surface of Fe3O4 (Fe3O4@SiO2) by hydrolysis and condensation of tetraethyl orthosilicate (TEOS) under alkaline medium at 80oC. It was found that only 500  mL TEOS is required to obtain the best coated Fe3O4 core structures which has been confirmed from its TEM micrograph. FTIR analyses revealed the formation of Si-O-Si bonds at 1084.2–1101.4 cm-1 hence confirmed that SiO2 has been successfully coated the Fe3O4 core. From the FESEM analyses, the average size of silica was ~ 50 -70 nm.  EDX of the Fe3O4@SiO2 showed that silica had been effectively bonded onto the surface of Fe3O4. The VSM measurements confirmed the superparamagnetic properties of Fe3O4@SiO2 that is desirable for biomedical applications.


Author(s):  
Arsalan Nikdoost ◽  
Alican Ozkan ◽  
Yusuf Kelestemur ◽  
Hilmi Volkan Demir ◽  
E. Yegan Erdem

This paper describes a method for the synthesis of silica nanoparticles that can be later used for coating of quantum dots inside a microfluidic reactor. Here, a droplet-based system is used where two reagents were mixed inside the droplets to obtain silica. Particles in the size range of 25±2.7 nm were obtained with comparable size distribution to controlled batch-wise synthesis methods. This method is suitable to be used later to coat CdSe nanoparticles inside the microreactor.


2020 ◽  
Vol 91 (3) ◽  
pp. 31301
Author(s):  
Nabil Chakhchaoui ◽  
Rida Farhan ◽  
Meriem Boutaldat ◽  
Marwane Rouway ◽  
Adil Eddiai ◽  
...  

Novel textiles have received a lot of attention from researchers in the last decade due to some of their unique features. The introduction of intelligent materials into textile structures offers an opportunity to develop multifunctional textiles, such as sensing, reacting, conducting electricity and performing energy conversion operations. In this research work nanocomposite-based highly piezoelectric and electroactive β-phase new textile has been developed using the pad-dry-cure method. The deposition of poly (vinylidene fluoride) (PVDF) − carbon nanofillers (CNF) − tetraethyl orthosilicate (TEOS), Si(OCH2CH3)4 was acquired on a treated textile substrate using coating technique followed by evaporation to transform the passive (non-functional) textile into a dynamic textile with an enhanced piezoelectric β-phase. The aim of the study is the investigation of the impact the coating of textile via piezoelectric nanocomposites based PVDF-CNF (by optimizing piezoelectric crystalline phase). The chemical composition of CT/PVDF-CNC-TEOS textile was detected by qualitative elemental analysis (SEM/EDX). The added of 0.5% of CNF during the process provides material textiles with a piezoelectric β-phase of up to 50% has been measured by FTIR experiments. These results indicated that CNF has high efficiency in transforming the phase α introduced in the unloaded PVDF, to the β-phase in the case of nanocomposites. Consequently, this fabricated new textile exhibits glorious piezoelectric β-phase even with relatively low coating content of PVDF-CNF-TEOS. The study demonstrates that the pad-dry-cure method can potentially be used for the development of piezoelectric nanocomposite-coated wearable new textiles for sensors and energy harvesting applications. We believe that our study may inspire the research area for future advanced applications.


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