Phase separation in PMMA/silica sol-gel systems

Kátia Fraga Silveira, Inez Valéria P. Yoshida, Suzana Pereira Nunes*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

76 Scopus citations


The mechanism of phase separation of sol-gel alkoxy-derived silica systems obtained by acid catalysis in the presence of poly(methyl methacrylate) (PMMA) and tetrahydrofuran was investigated by light scattering. Spinodal decomposition (SD) was confirmed for systems with intermediate PMMA/alkoxy compositions occurring with a simultaneous viscosity increase. The initial stages of phase separation followed the linear theory proposed by Cahn. For systems with low PMMA content, a behaviour typical of nucleation and growth was detected. In this case gelation took place after demixing. The morphology of the final PMMA/silica hybrid material was investigated by scanning and transmission electron microscopy with element-specific analysis. A matrix/disperse domains morphology was also verified for systems which demixed by SD, indicating that phase coarsening occurs. A micellar/lamellar microstructure was observed inside the separated phases.

Original languageEnglish (US)
Pages (from-to)1425-1434
Number of pages10
Issue number7
StatePublished - Mar 1995
Externally publishedYes


  • PMMA/silica
  • phase separation
  • sol-gel

ASJC Scopus subject areas

  • Organic Chemistry
  • Polymers and Plastics
  • Materials Chemistry


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