Journal article

Mesoporous silica matrices derived from sol-gel process assisted by low power ultrasonic activation

  • Savii, Cecilia Institute of Chemistry Timisoara of Romanian Academy, Romania
  • Almásy, László Laboratory for Neutron Scattering, PSI and ETH Zürich, Villigen, Switzerland - Adolphe Merkle Institute, University of Fribourg, Switzerland
  • Ionescu, Claudia Department of Physics, University of Warwick, United Kingdom
  • Székely, Noémi Kinga Research Institute for Solid State Physics and Optics, Budapest, Hungary
  • Enache, Corina Institute of Chemistry Timisoara of Romanian Academy, Romania
  • Popovici, Mihaela IMEC, Heverlee, Belgium
  • Sora, Ioan Faculty de Electrotechnics, University “Politehnica” Timisoara, Romania
  • Nicoara, Dan Faculty de Electrotechnics, University “Politehnica” Timisoara, Romania
  • Savii, George Gustav Faculty de Electrotechnics, University “Politehnica” Timisoara, Romania
  • Resiga, Dana Susan Faculty of Physics, West University of Timisoara, Romania
  • Subrt, Jan Department of Solid State Chemistry, Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic, Řež, Czech Republic
  • Štengl, Václav Department of Solid State Chemistry, Institute of Inorganic Chemistry, Academy of Sciences of the Czech Republic, Řež, Czech Republic
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    2009
Published in:
  • Processing and Application of Ceramics. - 2009, vol. 3, no. 1-2, p. 59-64
English The present work contributes to elucidating the differences between silica gels obtained by low doses ultrasonic activation, and those obtained by the conventional method, termed as classical sol gel. Silica matrices were produced by sol-gel synthesis process, assisted and non-assisted by an ultrasonic field, and subsequently characterized by various methods. Nitrogen adsorption and small-angle neutron scattering (SANS) measurements provided texture and microstructure of the dried gels. The adsorption results show that the sample sonicated for 2 hours presents the most ordered microstructure, characterized by pore shape close to spherical and the narrowest size distribution – about 90 % of the pores for this sample fall into the mesopore range (2–50 nm). SANS data reveal the formation of primary structural units of sizes around 1.5–2 nm which are small linear or branched polymeric species of roughly spherical shape and with rough surface. They are generated in the very early stage of sol gel process, as a result of hydrolysis and condensation reactions. The aggregated primary units form the secondary porous structure which can be described as a rough surface with fractal dimension above 2. The best porosity characteristics were obtained for the sample activated for 2 hours, indicating the optimal doses of sonication in the present conditions. Our results demonstrate the possibility of tailoring the pore size distribution using a low power ultrasonic bath.
Faculty
Faculté des sciences et de médecine
Department
Institut Adolphe Merkle
Language
  • English
Classification
Chemistry
License
License undefined
Identifiers
  • RERO DOC 12500
Persistent URL
https://folia.unifr.ch/unifr/documents/301339
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