Sol-gel nanometrology: gated sampling can reveal initial sol formation kinetics

C.D. Geddes, J. Karolin, D.J.S. Birch

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)


This report describes a gated sampling approach for studying the initial formation of sol-gel glasses prepared from sodium silicate solution (water glass) and sulphuric acid. Previously described were how changes in particle size and subsequently how sol-gel formation dynamics can be tracked using time-resolved fluorescence anisotropy, by labeling growing silica nanoparticles with suitable fluorescence probes. One limiting factor of this approach was the 2 minute measurement time, which limits this technique for studying the initial sol formation dynamics and limits the measurement precision. Using a continuous flow system and delaying sol flow through different tubing lengths overcomes this problem and allows monitoring of the very early stages of sol formation, second by second after sol preparation, irrespective of the anisotropy measurement time. This technique was applied to studying the initial formation dynamics, within the first 30 seconds, of a 12.01% SiO2 (w/w), pH 0.66 sol-gel, finding that silica particles of 1.5 nm mean radius are formed within 10 seconds of mixing the sol-gel.
Original languageEnglish
Pages (from-to)113-117
Number of pages4
JournalJournal of Fluorescence
Issue number1
Publication statusPublished - 1 Mar 2002


  • sol-gel
  • hydrogel
  • particle metrology
  • gated particle sampling
  • silica nanoparticles
  • nanoscience

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