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High specific surface area TEOS-based aerogels with large pore volume prepared at an ambient pressure

Title
High specific surface area TEOS-based aerogels with large pore volume prepared at an ambient pressure
Author
김희택
Keywords
silica aerogels; surface modification; ambient pressure drying; BET surface area; PSD; SEM
Issue Date
2007-11
Publisher
ELSEVIER SCIENCE BV
Citation
APPLIED SURFACE SCIENCE, v. 254, No. 2, Page. 574-579
Abstract
The experimental results on the synthesis of tetraethoxysilane (TEOS)-based silica aerogel with high specific surface area and large pore volume, via ambient pressure drying (APD) route, are reported. The silica aerogels were prepared by the acid-base sol-gel polymerization of TEOS precursor followed by the drying of the alcogels at an ambient pressure. The solvent present in the alcogel (i.e. ethanol) was replaced by a non-polar solvent such as hexane prior to the surface modification step. In order to minimize the drying shrinkage, the surface of the gels was modified using trimethylchlorosilane, (TMCS) before the APD. The FTIR spectra of the surface modified aerogels showed Si-CH3 peaks at 2965 and 850 cm(-1). The effect of the base catalyst (NH4OH) addition to the sol, at different time intervals (T), on the physical and textural properties of the resulting aerogels has been investigated. It has been observed that the surface area and the cumulative pore volume of the aerogels enhanced considerably from 819 to 1108 m(2) g(-1) and 2.65 to 4.7 cm(3) g(-1), respectively with an increase in the T value from 6 to 48 h. Silica aerogels with very low bulk density (0.06 g cm(-3)), extremely high specific surface area (1108 m(2) g(-1)) and large cumulative pore volume (4.7 cm(3) g(-1)) could be synthesized by drying the alcogels at the ambient pressure. The aerogels were mesoporous solids with the average pore size ranging from 12 to 17 rim. The results have been discussed by taking into consideration the hydrolysis and condensation reactions during the sol-gel polymerization of the TEOS precursor. (c) 2007 Elsevier B.V. All rights reserved.
URI
https://www.sciencedirect.com/science/article/pii/S0169433207008161https://repository.hanyang.ac.kr/handle/20.500.11754/107291
ISSN
0169-4332; 1873-5584
DOI
10.1016/j.apsusc.2007.06.063
Appears in Collections:
COLLEGE OF ENGINEERING SCIENCES[E](공학대학) > MATERIALS SCIENCE AND CHEMICAL ENGINEERING(재료화학공학과) > Articles
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