Sonogelling in boron alkoxides and visualization of “wet” boria microstructures by cryo-SEM
DSpace at IIT Bombay
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Title |
Sonogelling in boron alkoxides and visualization of “wet” boria microstructures by cryo-SEM
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Creator |
HARIDAS, MANOJ M
BELLARE, JAYESH |
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Subject |
scanning electron
ultrasonic applications microstructure hydrolysis |
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Description |
Gelling in tri-isopropoxy boron and a direct imaging characterization of its “wet” microstructures during sonogelling is reported for the first time in this article. The batch composition corresponds to an intimate blend of tri-isopropoxy boron, ethyl acetoacetate chelating agent, and isopropyl alcohol molecularly mixed using intense, contact-mode probe-type ultrasonication at 135 watts ultrasonic power. Chelation serves to retard the runaway alkoxide hydrolysis and sonogel the boria sol, gelling in which has so far not been reported due to its small molecular size and its amphoteric characteristics. The hydrolysis water was added at 0.4ml/h/g of alkoxide under controlled conditions of temperature, atmosphere and humidity. About 100μl of samples in varying stages of sonogelling were injected between two 300-mesh transmission electron microscopy (TEM) grids mounted on 0.1mm copper plates and plunged into melting freon at −160°C to cause a rapid solidification without vitrification. The sample was cryo-transferred into a scanning electron microscope (SEM), equipped with a liquid N2 cold stage maintained at −170°C. Cryo-SEM imaging at the sonogelling point shows a polymeric networking similar to that in alumina gels synthesized from aluminum sec-butoxide.
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Publisher |
Elsevier
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Date |
2009-02-14T07:21:27Z
2011-11-25T16:47:23Z 2011-12-26T13:05:33Z 2011-12-27T05:52:44Z 2009-02-14T07:21:27Z 2011-11-25T16:47:23Z 2011-12-26T13:05:33Z 2011-12-27T05:52:44Z 1999 |
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Type |
Article
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Identifier |
Materials Characterization 42(2-3), 55-63
1044-5803 http://dx.doi.org/10.1016/S1044-5803(98)00039-4 http://hdl.handle.net/10054/634 http://dspace.library.iitb.ac.in/xmlui/handle/10054/634 |
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Language |
en
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