TY - JOUR
T1 - Correlation between generated shear stress and generated permittivity for the electrorheological response of colloidal silica suspensions
AU - Saimoto, Yoshihisa
AU - Satoh, Tomoaki
AU - Konno, Mikio
N1 - Funding Information:
This work was supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science, Sports, and Culture, Japan (No. 09450282). The authors express their sincere gratitude to Professor Yasufumi Otsubo at Chiba University for valuable discussion and advice. They also thank Mr. Kazuyuki Sato for help in the preparation of a coaxial cylinder rheometer.
PY - 1999/11/1
Y1 - 1999/11/1
N2 - Electrorheological response was experimentally studied by the use of silicone oil suspensions containing submicrometer-sized and supermicrometer- sized silica particles with different amounts of adsorbed water. The simultaneous measurements of dielectric permittivity and shear stress of the suspensions were carried out after the application of alternating current voltage under steady shear in ranges of shear rate (150-1400 s-1), electric field strength (0-4 kV/mm), its frequency (30-1000 Hz), and particle volume fraction (0.1-0.3). For the particles with small amounts of adsorbed water, steady shear stress was attained within several minutes after the application of electric field. The steady-state data for both the particles at each electric field strength showed that the shear stress generated by the application of electric field, Δτ, varied correlatively with the generated permittivity, Δε(r) (= ε(r) - ε(r,oil), where ε(r) and ε(r,oil) are the permittivities of the suspension and the silicon oil, respectively. Under a wide variety of experimental conditions, the steady-state data for both the particle sizes could be correlated with a simple relationship, Δτ proportional to (Δε(r)E)2, where E is electric field strength. For the particles with large amounts of adsorbed water, steady state was not attained, and the evolutions of shear stress and permittivity of the suspensions were measured after the application of electric field. Remarkably, the transient values of Δτ varied with (Δε(r)E)2 and fell along the same correlation line as the steady-state data.
AB - Electrorheological response was experimentally studied by the use of silicone oil suspensions containing submicrometer-sized and supermicrometer- sized silica particles with different amounts of adsorbed water. The simultaneous measurements of dielectric permittivity and shear stress of the suspensions were carried out after the application of alternating current voltage under steady shear in ranges of shear rate (150-1400 s-1), electric field strength (0-4 kV/mm), its frequency (30-1000 Hz), and particle volume fraction (0.1-0.3). For the particles with small amounts of adsorbed water, steady shear stress was attained within several minutes after the application of electric field. The steady-state data for both the particles at each electric field strength showed that the shear stress generated by the application of electric field, Δτ, varied correlatively with the generated permittivity, Δε(r) (= ε(r) - ε(r,oil), where ε(r) and ε(r,oil) are the permittivities of the suspension and the silicon oil, respectively. Under a wide variety of experimental conditions, the steady-state data for both the particle sizes could be correlated with a simple relationship, Δτ proportional to (Δε(r)E)2, where E is electric field strength. For the particles with large amounts of adsorbed water, steady state was not attained, and the evolutions of shear stress and permittivity of the suspensions were measured after the application of electric field. Remarkably, the transient values of Δτ varied with (Δε(r)E)2 and fell along the same correlation line as the steady-state data.
KW - Dielectric permittivity
KW - Electric resistivity
KW - Electrorheology
KW - Silica particle
KW - Silicone oil
KW - Steady shear
KW - Suspension
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U2 - 10.1006/jcis.1999.6454
DO - 10.1006/jcis.1999.6454
M3 - Article
AN - SCOPUS:0033231491
VL - 219
SP - 135
EP - 143
JO - Journal of Colloid and Interface Science
JF - Journal of Colloid and Interface Science
SN - 0021-9797
IS - 1
ER -