Solid state radical recombination and charge transfer across the boundary between indomethacin and silica under mechanical stress

Tomoyuki Watanabe, Susumu Hasegawa, Naoki Wakiyama, Fusao Usui, Akira Kusai, Tetsuhiko Isobe, Mamoru Senna

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33 Citations (Scopus)


A composite of indomethacin (IM) and SiO2 was prepared in a solid state by cogrinding. Dehydration was observed as a consequence of a chemical reaction between silanol groups of SiO2 and carboxyl groups of IM. Several specific radical species found on separately ground SiO2 disappeared preferentially after cogrinding as a result of their recombination. These chemical interactions under mechanical stress bring about a charge transfer, as confirmed by X-ray photoelectron spectroscopy, leading to Si-O-C bridging bond formation at the IM/SiO2 interface.

Original languageEnglish
Pages (from-to)27-33
Number of pages7
JournalJournal of Solid State Chemistry
Issue number1
Publication statusPublished - 2002 Jan 1



  • Charge transfer
  • Electronegativity equalization
  • Mechanochemical
  • Mechanoradical
  • Silica composite

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Ceramics and Composites
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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