Swelling in water of a layered alkali silicate, octosilicate, modified with a sulfonic acid group

Yusuke Ide, Go Ozaki, Makoto Ogawa

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25 Citations (Scopus)

Abstract

A layered alkali silicate, octosilicate (Na2Si8O 17 ·nH2O), was functionalized with sulfonic acid to impart swelling ability in water. To immobilize the sulfonic acid group on octosilicate, (3-mercaptopropyl)trimethox- ysilane was attached in the interlayer space and subsequently oxidized. Surface coverage with the sulfonic acid group (0.7, 1.3, and 1.7 groups per Si8O17) was controlled by changing the added amount of the silane coupling reagent (0.7,1.3, and 2.0 groups per Si8O17). The sulfonated octosilicates hydrated to expand the interlayer space, where the degree of expansion varied with the surface coverage of sulfonic acid. For the sulfonated octosilicate with the lowest surface coverage (0.7 group per Si8O17), the remaining interlayer silanol group was efficiently grafted with the trimethylsilyl group to expand the interlayer space further upon hydration. The effect of the electrolyte concentration on the hydration of the sulfonated octosilicates was investigated to find that with the increase in NaCl concentration the basal spacing decreased. The sulfonated and trimethylsilylated octosilicates were dispersed in water to form colloidal suspensions with varied transparency.

Original languageEnglish
Pages (from-to)5276-5281
Number of pages6
JournalLangmuir
Volume25
Issue number9
DOIs
Publication statusPublished - 2009 May 5

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ASJC Scopus subject areas

  • Electrochemistry
  • Condensed Matter Physics
  • Surfaces and Interfaces
  • Materials Science(all)
  • Spectroscopy

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