Optically transparent silica aerogels based on sodium silicate by a two step sol-gel process and ambient pressure drying

Uzma K.H. Bangi, In Keun Jung, Chang Sun Park, Seungsu Baek, Hyung-Ho Park

Research output: Contribution to journalArticle

34 Citations (Scopus)

Abstract

Interest in improving the optical transmission of sodium silicate-based aerogels by ambient pressure drying led to the synthesis of aerogels using a two-step sol-gel process. To produce optically transparent silica aerogel granules, NH 4 F (1 M) and HCl (4 M) were used as hydrolyzing and condensation catalysts, respectively. The silica aerogels were characterized by their bulk density, porosity (%), contact angle and thermal conductivity. Optical transmission of as synthesized aerogels was studied by comparing the photos of aerogel granules. Scanning electron microscopic study showed the presence of fractal structures in these aerogels. The degree of transparency in two step sol-gel process-based aerogels is higher than the conventional single step aerogels. The N 2 adsorption-desorption analysis depicts that the two step sol-gel based aerogels have large surface areas. Optically transparent silica aerogels with a low density of ∼0.125 g/cc, low thermal conductivity of ∼0.128 W/mK and higher Brunauer, Emmett, and Teller surface area of ∼425 m 2 /g were obtained by using NH 4 F (1 M), HCl (4 M), and a molar ratio of Na 2 SiO 3 ::H 2 O:: trimethylchlorosilane of 1::146.67::9.46. The aerogels retained their hydrophobicity up to 500 °C.

Original languageEnglish
Pages (from-to)50-57
Number of pages8
JournalSolid State Sciences
Volume18
DOIs
Publication statusPublished - 2013 Feb 8

Fingerprint

sodium silicates
Aerogels
aerogels
sol-gel processes
Silicon Dioxide
Sol-gel process
drying
Silicates
Drying
Silica
Sodium
silicon dioxide
Light transmission
sodium silicate
Thermal conductivity
thermal conductivity
Hydrophobicity
hydrophobicity
Density (specific gravity)
Fractals

All Science Journal Classification (ASJC) codes

  • Chemistry(all)
  • Materials Science(all)
  • Condensed Matter Physics

Cite this

@article{1dbed94f57094e9da18e05f68b6e7a84,
title = "Optically transparent silica aerogels based on sodium silicate by a two step sol-gel process and ambient pressure drying",
abstract = "Interest in improving the optical transmission of sodium silicate-based aerogels by ambient pressure drying led to the synthesis of aerogels using a two-step sol-gel process. To produce optically transparent silica aerogel granules, NH 4 F (1 M) and HCl (4 M) were used as hydrolyzing and condensation catalysts, respectively. The silica aerogels were characterized by their bulk density, porosity ({\%}), contact angle and thermal conductivity. Optical transmission of as synthesized aerogels was studied by comparing the photos of aerogel granules. Scanning electron microscopic study showed the presence of fractal structures in these aerogels. The degree of transparency in two step sol-gel process-based aerogels is higher than the conventional single step aerogels. The N 2 adsorption-desorption analysis depicts that the two step sol-gel based aerogels have large surface areas. Optically transparent silica aerogels with a low density of ∼0.125 g/cc, low thermal conductivity of ∼0.128 W/mK and higher Brunauer, Emmett, and Teller surface area of ∼425 m 2 /g were obtained by using NH 4 F (1 M), HCl (4 M), and a molar ratio of Na 2 SiO 3 ::H 2 O:: trimethylchlorosilane of 1::146.67::9.46. The aerogels retained their hydrophobicity up to 500 °C.",
author = "Bangi, {Uzma K.H.} and Jung, {In Keun} and Park, {Chang Sun} and Seungsu Baek and Hyung-Ho Park",
year = "2013",
month = "2",
day = "8",
doi = "10.1016/j.solidstatesciences.2012.12.016",
language = "English",
volume = "18",
pages = "50--57",
journal = "Solid State Sciences",
issn = "1293-2558",
publisher = "Elsevier Masson SAS",

}

Optically transparent silica aerogels based on sodium silicate by a two step sol-gel process and ambient pressure drying. / Bangi, Uzma K.H.; Jung, In Keun; Park, Chang Sun; Baek, Seungsu; Park, Hyung-Ho.

In: Solid State Sciences, Vol. 18, 08.02.2013, p. 50-57.

Research output: Contribution to journalArticle

TY - JOUR

T1 - Optically transparent silica aerogels based on sodium silicate by a two step sol-gel process and ambient pressure drying

AU - Bangi, Uzma K.H.

AU - Jung, In Keun

AU - Park, Chang Sun

AU - Baek, Seungsu

AU - Park, Hyung-Ho

PY - 2013/2/8

Y1 - 2013/2/8

N2 - Interest in improving the optical transmission of sodium silicate-based aerogels by ambient pressure drying led to the synthesis of aerogels using a two-step sol-gel process. To produce optically transparent silica aerogel granules, NH 4 F (1 M) and HCl (4 M) were used as hydrolyzing and condensation catalysts, respectively. The silica aerogels were characterized by their bulk density, porosity (%), contact angle and thermal conductivity. Optical transmission of as synthesized aerogels was studied by comparing the photos of aerogel granules. Scanning electron microscopic study showed the presence of fractal structures in these aerogels. The degree of transparency in two step sol-gel process-based aerogels is higher than the conventional single step aerogels. The N 2 adsorption-desorption analysis depicts that the two step sol-gel based aerogels have large surface areas. Optically transparent silica aerogels with a low density of ∼0.125 g/cc, low thermal conductivity of ∼0.128 W/mK and higher Brunauer, Emmett, and Teller surface area of ∼425 m 2 /g were obtained by using NH 4 F (1 M), HCl (4 M), and a molar ratio of Na 2 SiO 3 ::H 2 O:: trimethylchlorosilane of 1::146.67::9.46. The aerogels retained their hydrophobicity up to 500 °C.

AB - Interest in improving the optical transmission of sodium silicate-based aerogels by ambient pressure drying led to the synthesis of aerogels using a two-step sol-gel process. To produce optically transparent silica aerogel granules, NH 4 F (1 M) and HCl (4 M) were used as hydrolyzing and condensation catalysts, respectively. The silica aerogels were characterized by their bulk density, porosity (%), contact angle and thermal conductivity. Optical transmission of as synthesized aerogels was studied by comparing the photos of aerogel granules. Scanning electron microscopic study showed the presence of fractal structures in these aerogels. The degree of transparency in two step sol-gel process-based aerogels is higher than the conventional single step aerogels. The N 2 adsorption-desorption analysis depicts that the two step sol-gel based aerogels have large surface areas. Optically transparent silica aerogels with a low density of ∼0.125 g/cc, low thermal conductivity of ∼0.128 W/mK and higher Brunauer, Emmett, and Teller surface area of ∼425 m 2 /g were obtained by using NH 4 F (1 M), HCl (4 M), and a molar ratio of Na 2 SiO 3 ::H 2 O:: trimethylchlorosilane of 1::146.67::9.46. The aerogels retained their hydrophobicity up to 500 °C.

UR - http://www.scopus.com/inward/record.url?scp=84873294890&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=84873294890&partnerID=8YFLogxK

U2 - 10.1016/j.solidstatesciences.2012.12.016

DO - 10.1016/j.solidstatesciences.2012.12.016

M3 - Article

VL - 18

SP - 50

EP - 57

JO - Solid State Sciences

JF - Solid State Sciences

SN - 1293-2558

ER -