Experimental results on electrorheology of liquid crystalline polymer solutions

Research output: Chapter in Book/Report/Conference proceedingConference contribution

3 Citations (Scopus)

Abstract

The electrorheological (ER) effect is known as the enhancement of the apparent viscosity upon application of an external electric field. Suspensions of polarizable particles in non-conducting solvents are the most studied electrorheological fluids, however, liquid crystalline materials may also present ER effect as long as their dielectric anisotropy is positive. In the liquid crystalline state of a positive dielectric anisotropy, the application of the electric field makes the director align perpendicular to the flow direction, thus increasing the apparent viscosity. In this work results of two liquid crystalline polymer solutions, acetoxypropylcellulose (APC) in dimethylacetamide (DMAc) and poly-γ-benzyl-L-glutamate (PBLG) in 1,4-dioxane, presenting opposite behavior upon application of the electric field, will be presented. APC/DMAc (negative dielectric anisotropy) presents a decrease of the apparent viscosity upon application of the electric field, as expected, while PBLG/1,4-dioxane (positive dielectric anisotropy) presents the opposite behavior. For this last solution we will present the shear flow curves for different electric fields in function of polymer molecular weight and solution concentration.

Original languageEnglish
Title of host publicationXVth International Congress on Rheology - The Society of Rheology 80th Annual Meeting
EditorsA. Co, L. G. Leal, R. H. Colby, A. J. Giacomin
PublisherAmerican Institute of Physics Inc.
Pages1429-1431
Number of pages3
VolumePts. 1 and 2
ISBN (Print)9780735405493
DOIs
Publication statusPublished - 11 Sep 2008
Event15th International Congress on Rheology - Monterey, CA, United States
Duration: 3 Aug 20088 Aug 2008

Publication series

NameAIP Conference Proceedings
PublisherAmerican Institute of Physics Inc.
Volume1027
ISSN (Print)0094-243X
ISSN (Electronic)1551-7616

Conference

Conference15th International Congress on Rheology
CountryUnited States
CityMonterey, CA
Period3/08/088/08/08

Keywords

  • electrorheology
  • PBLG
  • liquid crystalline polymers

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