Advertisement

Structural characteristics of sheared suspensions of hydrated colloids

  • F. Le Berre
  • E. PefferkornEmail author
Polymer Colloids
Part of the Progress in Colloid & Polymer Science book series (PROGCOLLOID, volume 110)

Abstract

The mass and size frequencies of aggregates formed under low shear by encounters between hydrated colloids of micrometric size was investigated under marginal stability conditions. The mass c(n) and size c(d) frequency curves were determined by particle counting and laser diffractometry, respectively. Correlation between reduced mass and size distributions unequivocally led to the fractal dimension of the aggregates. Aggregation/fragmentation under low shear rate gave rise to aggregates of relatively low fractal dimension when compared to situations of high shear rates. Under marginal stability conditions, the particle concentration and ionic strength differently induced the aggregate formation. In 0.15 M NaCl suspension, aging effects were determined above a threshold concentration while in 0.075 M NaCl suspension, aging effects were observed at all concentrations. Aggregation/fragmentation in 0.15 M NaCl suspensions led to aggregates of fractal dimension 1.4 while in 0.075 M NaCl suspensions, aging and restructuration led to aggregates of fractal dimension 1.8. These relatively low values of the fractal dimension were interpreted by the existence of a preferential orientation of the aggregates in the low shear flow.

Key words

Orthokinetic aggregation aggregate mass distribution aggregate size distribution hydrated colloids aggregation in a Couette system aggregate fractal dimension 

Preview

Unable to display preview. Download preview PDF.

Unable to display preview. Download preview PDF.

References

  1. 1.
    Valioulis IA (1986) Adv Colloid Interface Sci 24:81CrossRefGoogle Scholar
  2. 2.
    Pierzynski GM, Sims JT, Vance GF (eds) (1993) Soils and Environmental Quality. Lewis Publishers, Boca RatonGoogle Scholar
  3. 3.
    Le Berre F, Chauveteau G, Pefferkorn EJ (1998) Colloid Interface Sci 199:1CrossRefGoogle Scholar
  4. 4.
    Buffle J, van Leuven HP (1992) Environmental Particles. IUPAC Environmental Analytical and Physical Chemistry Series. IUPAC, Chelsea, MIGoogle Scholar
  5. 5.
    Family F, Landau DP (eds) (1984) Kinetics of Aggregation and Gelation. North-Holland, AmsterdamGoogle Scholar
  6. 6.
    Stanley HE, Ostrowsky N (eds) (1986) On Growth and Form. Nijhoff, DordrechtGoogle Scholar
  7. 7.
    Jullien R, Botet R (1989) Aggregation and Fractal Aggregates. World Scientific, SingaporeGoogle Scholar
  8. 8.
    Vicsek T (1989) Fractal Growth Phenomena. World Scientific, SingaporeGoogle Scholar
  9. 9.
    Walker PH, Hutka J (1971) In Division if Soils. Tech Paper 1, 3Google Scholar
  10. 10.
    Pefferkorn E (1995) Adv Colloid Interface Sci 56:33CrossRefGoogle Scholar
  11. 11.
    Swift DL, Friedlander SK (1964) J Colloid Sci 19:621CrossRefGoogle Scholar
  12. 12.
    Lushnikov AA (1973) J Colloid Interface Sci 45:549CrossRefGoogle Scholar
  13. 13.
    Singer JK, Anderson JB, Ledbetter MT, McCave LR, Jones KPN, Wright R (1988) J Sediment Petrol 58:534Google Scholar
  14. 14.
    Bos MTA, van Opheusden JHJ (1996) Phys Rev E 53:5044CrossRefGoogle Scholar
  15. 15.
    Hurd A, Schaefer D (1985) Phys Rev Lett 54:1043CrossRefGoogle Scholar
  16. 16.
    Hurd AJ, Flower WL (1988) J Colloid Interface Sci 122:178CrossRefGoogle Scholar
  17. 17.
    Meakin P, Chen Z-Y, Evesque P (1987) J Phys Chem 87:630CrossRefGoogle Scholar
  18. 18.
    Jullien R (1985) Phys Rev Lett 55:1697CrossRefGoogle Scholar
  19. 19.
    Meakin P, Muthukumar M (1989) J Phys Chem 91:3212CrossRefGoogle Scholar
  20. 20.
    Meakin P (1990) J Colloid Interface Sci 134:235CrossRefGoogle Scholar

Copyright information

© Dr. Dietrich Steinkopff Verlag GmbH & Co. KG 1998

Authors and Affiliations

  1. 1.Institut Charles SadronStrasbourg CedexFrance

Personalised recommendations