Colloid and Polymer Science

, Volume 273, Issue 12, pp 1156–1162 | Cite as

Field-induced structural ordering in electrorheological fluids

  • P. Placke
  • V. Edel
  • L. Reversat
  • R. Richert
  • E. W. Fischer
Original Contribution

Abstract

Structural relaxations of an electrorheological fluid (ERF) due to changes in the applied electrical field strength or shear rate are observed on time scales 1 s<t<40 000 s. Commercial ERFs consisting of mesoscopic polyurethane particles in a silicone oil matrix were studied by three different experimental techniques in order to obtain and compare the characteristic relaxation times. It is demonstrated that dielectric spectroscopy, viscosimetry and light transmission experiments represent the same results concerning the structural relaxation phenomena of ERFs when electrical fields are applied. The tendency of strong induced dipoles to align the particles in the direction of the field increases the effective dipole moment and therefore Δε, the shear viscosity ν and the amount of light transmitted along the field direction in an ITO/glass sandwich cell. The optical experiment is capable of resolving fast processes within the first 1 ms if large electrical fields are applied. The effects of electrophoresis and shearing, which both counteract the field induced structures, are also addressed.

Key words

Electrorheological fluids colloids rheodielectric spectroscopy light transmission 

References

  1. 1.
    Ginder JM (1993) Phys Rev E 47:3418Google Scholar
  2. 2.
    Haas KC (1993) Phys Rev E 47:3362Google Scholar
  3. 3.
    Halsey TC (1992) Science 258:761Google Scholar
  4. 4.
    Klingenberg DJ, van Swol F, Zukoski CF (1991) J Chem Phys 94:6170Google Scholar
  5. 5.
    Adolf D, Garino T, Hance B (1995) Langmuir 11:313Google Scholar
  6. 6.
    Anderson RA (1994) Langmuir 10:2917Google Scholar
  7. 7.
    Davis LC (1992) J Appl Phys 72:1334Google Scholar
  8. 8.
    Tao R, Roy GD (Eds) (1993) Proceedings of the Third International Conference on Electrorheological Fluids, World Scientific, SingaporeGoogle Scholar
  9. 9.
    Böttcher CJF (1973) Theory of Electric Polarization, Vol 1, Elsevier, Amsterdam; Böttcher CJF, Bordewijk P (1978) Theory of Electric Polarization, Vol II, Elsevier, AmsterdamGoogle Scholar
  10. 10.
    Bloodworth R, Wendt E (1994) Polymer Preprints 35:356Google Scholar
  11. 11.
    Bayer AG, Leverkusen (1994) Provisional product information, Bayer SiliconeGoogle Scholar
  12. 12.
    Placke P, Richert R, Fischer EW (1995) Colloid Polym Sci 273:848Google Scholar
  13. 13.
    Gast AP, Zukoski CF (1989) Adv Coll and Interf Sci 30:153Google Scholar
  14. 14.
    Block H, Kelly JP (1988) J Phys D: Appl Phys 21:1661Google Scholar
  15. 15.
    Bossis G, et al. (1994) Europhys Lett 25:335Google Scholar
  16. 16.
    Adolf D, Garino T (1995) Langmuir 11:307Google Scholar

Copyright information

© Steinkopff Verlag 1995

Authors and Affiliations

  • P. Placke
    • 1
  • V. Edel
    • 1
  • L. Reversat
    • 1
  • R. Richert
    • 1
  • E. W. Fischer
    • 1
  1. 1.Max-Planck-Institut für PolymerforschungMainzGermany

Personalised recommendations