Porous properties of silica gels with controlled morphology synthesized by unidirectional freeze-gelation

Shin R. Mukai, Hirotomo Nishihara, Hajime Tamon

Research output: Contribution to journalArticlepeer-review

65 Citations (Scopus)

Abstract

In this work, the unidirectional freezing method was applied to a wide variety of silica gel precursors; from silica sols which do not readily gel, to thoroughly aged silica hydrogels. It was found that in addition to the well-known structure of fibers with polygonal cross-sections which are commonly obtained in the unidirectional freezing method, porous silica gels having unique morphologies such as honeycomb, lamellar and flat fiber structures could also be obtained by changing the state of the precursor sol or gel. The obtained silica hydrogels were freeze-dried after exchanging the water included in its structure to t-butanol, and finally dry samples maintaining their wet state structures were obtained. The morphology and the porous properties of the obtained silica gels were systematically analyzed and the influences of preparation conditions, including pH, aging time before freezing, SiO2 concentration, freezing temperature, and storage time at the frozen state on both factors were examined in detail. It was found that the simultaneous controlling of both factors could be easily conducted by simply adjusting preparation conditions.

Original languageEnglish
Pages (from-to)43-51
Number of pages9
JournalMicroporous and Mesoporous Materials
Volume63
Issue number1-3
DOIs
Publication statusPublished - 2003 Sep 18
Externally publishedYes

Keywords

  • Morphology
  • Porous properties
  • Silica gel
  • Sol-gel processes
  • Unidirectional freeze-gelation

ASJC Scopus subject areas

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

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