Template-Free Synthesis of Ellipsoidal Silica Nanoparticles

2012 ◽  
Vol 1386 ◽  
Author(s):  
Henan Zhang ◽  
Daniel L. Akins

ABSTRACTFor a sol-gel process occurring in a water/oil (w/o) system, the self-assembly of silica nuclei can be controlled by close control of synthesis conditions. We have synthesized ellipsoidal or spherical silica particles by a template-free scheme that involves controlling surface tension on silica nuclei through via use of different volume ratios of a w/o micellar system.

2013 ◽  
Vol 773 ◽  
pp. 606-610
Author(s):  
Jing Li ◽  
Hong Qi Zhang ◽  
Wei Xue

Spherical silica particles, with mean sizes about 1.2 μm, were prepared through TEOS sol-gel process catalyzed by ammonia. The silica particles have a smooth surface and a small specific surface area, 3.4 m2/g. The sol-gel process was monitored by React IRTMusing an in-situ technique. Based on the measurements, mechanism of TEOS hydrolyzation and succedent condensation polymerization was inferred. With the adding of ammonia, OH-anion attacks Si atomic nucleus directly and makes it showing negative electricity. Therefore the electron cloud shifts to the OR group on the other side. This weakens the Si-O bond and results in the removal of the OR group. Furthermore, silanol, generated from TEOS hydrolyzation, attracts Si-OR or other Si-OH around; thereby resulting rapid dehydration or dealcohol between molecular. So the condensation polymerization rate is elevated, and Si-O-Si bond comes into being. Lastly, cross-linking reaction among Si-O-Si bonds forms the particle.


2005 ◽  
Vol 873 ◽  
Author(s):  
Michael R. Weatherspoon ◽  
Shawn M. Allan ◽  
Christopher S. Gaddis ◽  
Ye Cai ◽  
Michael S. Haluska ◽  
...  

AbstractControlled-shape BaTiO3-based microparticles were synthesized with the use of diatom microshells (frustules) as templates. The SiO2-based frustules of Aulacoseira diatoms were first converted into MgO-based replicas via a gas/solid displacement reaction at 900°C. A BaTiO3 coating was then applied to the MgO-bearing frustules by a sol-gel process. After firing at 700°C for 1.5 h, a conformal nanocrystalline coating of BaTiO3was generated on the surfaces of the MgO-bearing frustules. The underlying MgO scaffolds were then selectively dissolved away to yield freestanding 3-D BaTiO3-based replicas of the original Aulacoseira diatom frustules. This work demonstrates that microparticles with well-controlled 3-D morphologies and non-natural multicomponent ceramic compositions can be produced by merging the self-assembly ability of biomineralizing micro-organisms with synthetic chemical tailoring.


2010 ◽  
Vol 20 (43) ◽  
pp. 9684 ◽  
Author(s):  
Shanmugam Easwaramoorthi ◽  
Pyosang Kim ◽  
Jong Min Lim ◽  
Suhee Song ◽  
Honsuk Suh ◽  
...  
Keyword(s):  
The Self ◽  

2020 ◽  
Vol 141 ◽  
pp. 105540
Author(s):  
Linlong Meng ◽  
Haoxin Zhu ◽  
Bing Feng ◽  
Zhenhua Gao ◽  
Di Wang ◽  
...  

2008 ◽  
Vol 19 (8) ◽  
pp. 977-983 ◽  
Author(s):  
Kiyomi Fuchigami ◽  
Yoshinari Taguchi ◽  
Masato Tanaka

2016 ◽  
Vol 40 (1) ◽  
pp. 589-595 ◽  
Author(s):  
Hui Yang ◽  
Yuan Xie ◽  
Guisong Hao ◽  
Weiwei Cai ◽  
Xingzhong Guo

Porous alumina microspheres prepared via a facile template-free approach followed by heat-treatment, exhibiting a three-dimensional interconnected structure.


CrystEngComm ◽  
2014 ◽  
Vol 16 (34) ◽  
pp. 7881-7884 ◽  
Author(s):  
Kay He ◽  
Gaoling Zhao ◽  
Gaorong Han

TiO2 microspheres with tunable particle size were prepared in alcohols without a template via a facile non-aqueous sol–gel process, on the basis of an ester elimination mechanism.


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