Evolution of porosity and morphology in alkylene-bridged polysilsesquioxane xerogels as a function of gel aging time

Douglas A. Loy, James H. Small, Kimberly A. DeFriend, Kennard V. Wilson, McKenzie Minke, Brigitta M. Baugher, Colleen R. Baugher, Duane A. Schneider, Kenneth J. Shea

Research output: Contribution to journalConference articlepeer-review

1 Scopus citations


Aging of silica gels before drying is known to result in significant changes in xerogel morphology, porosity and properties. In this study, the influence of aging gels on the porosity and morphology of alkylene-bridged polysilsesquioxane xerogels was examined. Gels of hexylene-. heptylene, octylene, nonylene, and decylene-bridged polysilsesquioxanes were prepared by the sol-gel polymerization of the respective bis(trimethoxysilyl)alkane monomers under acidic or basic conditions in methanol and in tctrahydrofuran. The gels were aged 3,7.14. 28, 35, 42, 49, and 56 days before drying to afford xerogels. The xerogels were characterized by nitrogen sorption porosimetry. Xerogels prepared in THF were non-porous. Those prepared and aged under basic conditions in methanol or tetrahydrofuran exhibited coarsening of porosity with aging time. With the exception of the hexylene-bridged gels, those prepared and aged in acidic methanol showed little change with aging. The surface area of the hexylene-bridged xerogels nearly tripled with aging times of up to several weeks, then decreased, for the gels aged for more than two weeks, to around 100 meters squared per gram.

Original languageEnglish (US)
Article numberEE10.3
Pages (from-to)99-106
Number of pages8
JournalMaterials Research Society Symposium Proceedings
StatePublished - 2005
Event2004 Materials Research Society Fall Meeting - Boston, MA, United States
Duration: Nov 30 2004Dec 3 2004

ASJC Scopus subject areas

  • General Materials Science
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering


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