Porous gel coatings obtained by phase separation in ORMOSIL system

K. Nakanishi, S. Kumon, K. Hirao, H. Jinnai

Research output: Contribution to journalConference article

3 Citations (Scopus)

Abstract

Macroporous silicate thick films were prepared by a sol-gel dip-coating method accompanied by the phase separation using methyl-trimethoxysilane (MTMS), nitric acid and dimethylformamide (DMF) as starting components. The morphology of the film varied to a large extent depending on the time elapsed after the hydrolysis until the dipping of the coating solution. On a glass substrate, the films prepared by early dipping had inhomogeneous submicrometer-sized pores on the surface of the film. At increased reaction times, relatively narrow sized isolated macropores were observed and their size gradually decreased with the increase of reaction time. On a polyester substrate, in contrast, micrometer-sized isolated spherical gel domains were homogeneously deposited by earlier dippings. With an increase of reaction time, the volume fraction of the gel phase increased, then the morphology of the coating transformed into co-continuous gel domains and macropores, and finally inverted into the continuous gel domains with isolated macropores. The overall morphological variation with the reaction time was explained in terms of the phase separation and the structure freezing by the forced gelation, both of which were induced by the evaporation of methanol during the dipping operation.

Original languageEnglish
Pages (from-to)CC7.6.1-CC7.6.11
JournalMaterials Research Society Symposium - Proceedings
Volume628
DOIs
Publication statusPublished - 2000
Externally publishedYes
EventOrganic/Inorganic Hybrid Materials-2000 - San Francisco, CA, United States
Duration: 2000 Apr 242000 Apr 28

ASJC Scopus subject areas

  • Materials Science(all)
  • Condensed Matter Physics
  • Mechanics of Materials
  • Mechanical Engineering

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