Rheodielectric spectroscopy on heterogeneous polymer systems -electrorheological fluids

P. Placke, Ranko Richert, E. W. Fischer

Research output: Contribution to journalArticle

8 Citations (Scopus)

Abstract

The technique of rheodielectric spectroscopy is used to investigate the dielectric behaviour of electrorheological fluids (ERF) as a function of external electrical DC-field and/or shear rate. Commercial ERF's consisting of mesoscopic polyurethane particles in a silicone oil matrix were studied. The particles contain a salt which leads to strong dipole moments via the Maxwell-Wagner-Polarization (MWP) if subjected to an external electrical field. In an electrical field the dipoles and, concomittantly, the particles motion become correlated leading to the formation of solid-like structures and significant changes in the viscosity. We demonstrate that dielectric spectroscopy is capable of monitoring the field and shear rate effects in terms of relaxation strength and relaxation time of the MWP. In electrical or shear fields dipole-dipole correlations increase the MWP's relaxation strength, so that we are able to observe structure formation with dielectric spectroscopy, especially the time resolved response of the ERF to changes in the electrical field or the shear rate.

Original languageEnglish (US)
Pages (from-to)848-856
Number of pages9
JournalColloid & Polymer Science
Volume273
Issue number9
DOIs
StatePublished - Sep 1995
Externally publishedYes

Fingerprint

Electrorheological fluids
electrorheological fluids
Shear deformation
Dielectric spectroscopy
Polymers
Spectroscopy
shear
polymers
dipoles
Polarization
spectroscopy
Silicone Oils
Polyurethanes
Dipole moment
Silicones
Relaxation time
particle motion
silicones
polarization
Salts

Keywords

  • colloidal suspensions
  • dielectric spectroscopy
  • Electrorheological fluids

ASJC Scopus subject areas

  • Polymers and Plastics
  • Materials Chemistry
  • Physical and Theoretical Chemistry
  • Colloid and Surface Chemistry

Cite this

Rheodielectric spectroscopy on heterogeneous polymer systems -electrorheological fluids. / Placke, P.; Richert, Ranko; Fischer, E. W.

In: Colloid & Polymer Science, Vol. 273, No. 9, 09.1995, p. 848-856.

Research output: Contribution to journalArticle

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