Clays and Clay Minerals

, Volume 44, Issue 2, pp 197–213 | Cite as

Study of a Commercial SiO2 Sol and Gel By Small Angle X-Ray Scattering: Effect of Sample Thickness and Interpretation by Means of Smoluchowski Scheme

  • Yingnian Xu
  • Pang L. Hiew
  • Matthew Akira Kuppenstein
  • Yoshikata Koga


Ludox HS SiO2 sols at high concentrations show a peak in small angle x-ray scattering (SAXS) reminiscent to a “structure.” The appearance of such a peak was found to depend crucially on the thickness of the sample cell used for SAXS measurements. The thinner the cell used, the more prominent the peak. When the thickness was larger than 2 mm, it was no longer observable. When sols were treated with activated charcoal powders (in order to remove a surfactant) the peak became less prominent.

For the cases where clear features for structure were absent (thick sample regime), the Smoluchowski scheme was utilized to study the nature of sols. Namely, the distribution of the Smoluchowski species were estimated by numerically calculating the size distribution of particles directly from SAXS data. The distribution was found basically bimodal, and the main distribution peak, particularly for dilute sols (less than 5 wt%), was consistent with primary particles of SiO2. The second distribution peak was strongly dependent on the concentration of SiO2 particles. The observed trend was that the higher the concentration of SiO2 particles, the more prominent the second distribution peak and the locus of the maximum tended to move toward a smaller value in diameter. This behavior of the second distribution peak of the Smoluchowski species is no doubt a manifestation of the interparticle correlation. The observation of such behavior may provide a convenient means to characterize sols with interparticle correlation. This method was also applied for characterizing gels formed when the pH values were altered.

Key Words

Dependence of Sample Thickness Ludox HS SiO2 SAXS Smoluchowski Scheme Structure in sol 


Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.


  1. Allen LH, Matijevic E. 1969. Stability of colloidal silica: I. Effect of simple electrolytes. J Coll Interf Sci 31:287–296.Google Scholar
  2. Barta L, Kooner ZS, Hepler LG, Roux-Dosgranges G, Grolier J-PE. 1989. Thermal and volumetric properties of chloroform + dimethlsulfoxide: thermodynamic analysis using the ideal associated solution model. J Sol Chem 18:663–673.Google Scholar
  3. Bhatia AB. 1984. On the zero wavenumber factors of binary associating mixtures. Phys Chem Liq 13:241–253.Google Scholar
  4. Blinker CJ, Scherer GN. 1990. Sol-gel Science—The physics and chemistry of sol-gel processing. San Diego: Academic Press 331p.Google Scholar
  5. Bunce J, Ramsay JDE 1985. Small-angle neutron-scattering studies of silica sols in water at high temperatures. J Chem Soc, Faraday Trans 1 81:2845–2854.Google Scholar
  6. Costas M, Patterson DP. 1985. Heat capacities of water+organic-solvent mixtures. J Chem Soc, Faraday Trans 1 81:2381–2398.Google Scholar
  7. Dethelfson C, Sorensen PG, Hvidt Aa. 1984. Excess volumes of propanol-water mixtures at 5, 15 and 25°C. J Sol Chem 13:191–202.Google Scholar
  8. Everett DH. 1989. Basic principles of colloid science. London: Royal Society of Chemistry. 159p.Google Scholar
  9. Franks F, Desnoyers JE. 1985. Alcohol-water mixtures revisited. In:Franks F, editor. Water science reviews 1. London: Cambridge Univ. Press. 171–232Google Scholar
  10. Groot RD. 1990. Recent theories on the electric double layer. In:Bloor DM, Wyn-Jones E, editors. The structure, dynamics, and equilibrium properties of colloidal systems. The Netherlands: Kluumer Academic Press; 801–812.Google Scholar
  11. Groot RD. 1991. On the equation of state of charged colloidal systems. J Chem Phys 94:5083–5089.Google Scholar
  12. Guinier A, Fournet G. 1955. Small-angle Scattering of X-rays. New York: John Wiley and Sons. 149–151.Google Scholar
  13. Handa YP, Zakrzewski M, Fairbridge C. 1992. Effect of restricted geometries on the structure and thermodynamic properties of ice. J Phys Chem 95:8594–8599.Google Scholar
  14. Matsuoka H, Tanaka H, Hashimoto T, Ise N. 1987. Elastic scattering from cubic lattice systems with paracrstalline distortion. Phys Rev B 36:1754–1765.Google Scholar
  15. Matsuoka H, Murai H, Ise N. 1988. “Ordered” structure in collodial silica particle suspensions as studied by small-angle x-ray scattering. Phys Rev B 37:1368–1375.Google Scholar
  16. Milonjic SK. 1992. A relation between the amounts of sorbed alkali cations and the stability of colloidal silica. Coll & Surfaces 63:113–119.Google Scholar
  17. Monkenbusch M. 1991. DEMUXMUX: removal of multiple scattering from small-angle data. J Appl Cryst 24:955–958.Google Scholar
  18. Moonen JAHM. 1987. Small angle scattering of colloidal dispersions [Ph.D. thesis]. The Netherlands: Univ. Utrecht. 137p.Google Scholar
  19. Nikolov AD, Wasan DT. 1992. Dispersion stability due to structural contributions to the particle interaction as probed by thin liquid film dynamics. Langmuir 8:2985–2994.Google Scholar
  20. Penfold J, Ramsay JDF. 1985. Studies of electrical double-layer interactions in concentrated silica sols by small-angle neutron scattering. J Chem Soc, Faraday Trans 1 81:117–125.Google Scholar
  21. Ramsay JDF, Booth BO. 1983. Determination of structure in oxide sols and gels from neutron scattering and nitrogen adsorption measurements. J Chem Soc, Faraday Trans 1 79: 173–184.Google Scholar
  22. Ramsay JDF, Avery RG, Benest L. 1983. Neutron-scattering studies of concentrated oxide sols. Faraday Discuss, Chem Soc 76:53–63.Google Scholar
  23. Schaefer D, Martin JE, Cannell D, Wiltzins P. 1984. Fractal geometry of colloidal aggregates. Phys Rev Lett 52:2371–2374.Google Scholar
  24. Schelten J, Schmatz W. 1980. Multi-Scattering treatment for small-angle scattering problems. J Appl Cryst 13:385–390.Google Scholar
  25. Shuin T. 1977. Small-angle x-ray scattering analysis of particle size distributions of colloidal SiO2 sol. Jpn J Appl Phys 16:539–548.Google Scholar
  26. Sogami I, Ise N. 1984. On the electrostatic interaction in macroionic solutions. J Chem Phys 81:6320–6332.Google Scholar
  27. Valleau JP, Ivkov R, Torrie GM. 1991. Colloid stability: the forces between charged surfaces in an electrolyte. J Chem Phys 95:520–532.Google Scholar
  28. Vonk CG. 1975. A general computer program for the processing of small-angle x-ray scattering data. J Appl Cryst 8:340–341.Google Scholar
  29. Vonk CG. 1976. On two methods for determination of particle size distribution functions by means of small-angle x-ray scattering. J Appl Cryst 9:433–440.Google Scholar
  30. Vonk CG, Pijpers AP. 1981. The use of film methods in small-angle x-ray scattering. J Appl Cryst 14:8–16.Google Scholar
  31. Vonk CG. 1988. A reevaluation of film methods in x-ray scattering. Rigaku J 5:9–17.Google Scholar
  32. Wasan DT, Nikolov AD, Kralchevsky PA, Ivanov IB. 1992. Universality in film stratification due to colloid crystal formation. Coll & Surfaces 67:139–145.Google Scholar
  33. Xu Y, Koga Y, Watkinson AP. 1994. Pore size distribution of coals and chars from Western Canada. Fuel 73:1797–1801.Google Scholar
  34. Xu Y, Chan SP, Koga Y Personal communication. Department of Chemistry. The University of British Columbia, Vancouver, B.C., Canada V6T 121.Google Scholar
  35. Zerrouk R, Foissy A, Mercier R, Chevallier Y Morawski J-C. 1990. Study of Ca2+-induced silica coagulation by small angle scattering. J Coll Interf Sci 139:20–29.Google Scholar

Copyright information

© The Clay Minerals Society 1996

Authors and Affiliations

  • Yingnian Xu
    • 1
  • Pang L. Hiew
    • 1
  • Matthew Akira Kuppenstein
    • 1
  • Yoshikata Koga
    • 2
  1. 1.Department of ChemistryThe University of British ColumbiaVancouverCanada
  2. 2.Center for Ceramics Research, Research Laboratory of Engineering MaterialsTokyo Institute of Technology NagatsutaYokohamaJapan

Personalised recommendations