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Sedimentation‐resistant electrorheological fluids based on PVAL‐coated microballoons
Author(s) -
Qi Mancun,
Shaw Montgomery T.
Publication year - 1997
Publication title -
journal of applied polymer science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.575
H-Index - 166
eISSN - 1097-4628
pISSN - 0021-8995
DOI - 10.1002/(sici)1097-4628(19970718)65:3<539::aid-app13>3.0.co;2-s
Subject(s) - electrorheological fluid , materials science , rheology , composite material , shear (geology) , breakage , dimensionless quantity , sedimentation , electric field , thermodynamics , geology , physics , paleontology , quantum mechanics , sediment
Sedimentation is often a problem in electrorheological (ER) fluids featuring solid particles suspended in a low‐density hydrocarbon oil. This problem was addressed by synthesizing particles comprising silica microballoons coated with PVAL using a salt‐induced coacervation process. The ER performance of the fluids based on these particles was equivalent to prototypical commercial fluids, both with respect to current leakage and shear stress under steady simple shear flow. For comparing diverse fluids as to these practical characteristics, a dimensionless ER effectiveness number, Er, was proposed: Er = σγ˙/ EJ where σ is the shear stress, γ˙ is the electric field, and J is the current. The resulting uniform coatings were also found to impart a degree of resistance to breakage. © 1997 John Wiley & Sons, Inc. J Appl Polym Sci 65:539–547, 1997