Electrorheological properties of a mixture of two immiscible fluids having the same viscosity

ABSTRACT:The synthesis, characterization, partial hydrolysis, and salt formation of polyisoprene-co-poly(tert-butyl methacrylate) and the electrorheological properties of its suspensions were investigated. The copolymer was characterized by gel permeation chromatography, viscosity measurements, 1 H-NMR, Fourier transform infrared spectroscopy, particle size measurements, and elemental analysis. The poly(tert-butyl methacrylate) units of the copolymer were partially hydrolyzed by p-toluene sulfonic acid monohydrate and then converted into a lithium salt. The conductivity of this copolymeric salt was measured to be 1.4 ϫ 10 Ϫ9 S cmϪ1 . Suspensions of the copolymeric salt were prepared in four insulating oils (silicone oil, mineral oil, trioctyl trimellitate, and dioctyl phatalate) in a series of concentrations (5-33%, m/m). The gravitational stabilities of these suspensions were determined at 20 and 80°C. The flow times of the suspensions were measured under no electric field (electric field strength ϭ 0) and under an applied electric field (electric field strength 0), and the electrorheological activity was observed. Furthermore, the effects of the solid particle concentration, the shear rate, the electric field strength, a high temperature, and the addition of promoters on the electrorheological activities of the suspensions were investigated, and the excess shear stresses were determined.

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“…A similar trend was observed by Orihara et al27 in ER studies of liquid‐crystal polymer blend suspensions prepared in SO.…”

Section: Resultssupporting

confidence: 88%

Synthesis, characterization, and partial hydrolysis of polyisoprene‐co‐poly(tert‐butyl methacrylate) and electrorheological properties of its suspensions

Yavuz

Ünal

2003

J of Applied Polymer Sci

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“…The shear rate was measured at the edge of the rotating disk, and the shear stress was calculated from the measured torque under the assumption of a Newtonian fluid because a parallel-plate rheometer was used in the experiment. Although immiscible polymer blends under an electric field are not generally Newtonian [19], the above assumption is not considered to seriously affect our conclusions in this paper because the contribution to the stress around the edge is dominant and we only roughly estimate the shear stress. Observations were made through the bottom glass plate with a CSLM (IX71, Olympus and CSU22, Yokogawa).…”

Section: Methodsmentioning

confidence: 99%

Three-dimensional observation of an immiscible polymer blend subjected to a step electric field under shear flow

et al. 2011

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We have investigated the structural change of an immiscible blend consisting of two polymers with equal viscosity subjected to a step electric field under shear flow. During the process, three-dimensional images were successfully acquired with a confocal scanning laser microscope, and at the same time, the transient shear stress was also measured. From the images, the interface tensor was calculated. In a blend of polymers with equal viscosity, the total shear stress may consist of the viscous, interfacial, and electric stresses. An experiment was performed to separate these stresses, and the results are discussed in terms of the interface tensor.

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“…The immiscible ER blends exhibit various ER effects depending not only on the nature of the components but also on their composition. It is interesting that even in a mixture of LCP and DMS having the same viscosity show an ER effect [64]. By using the different temperature dependence between the LCP and DMS, it is possible to prepare various blends in which the two components have different or the same viscosity by changing the temperature.…”

Section: Ch3mentioning

confidence: 99%

Electro- and Magneto-Rheological Materials: Stimuli-Induced Rheological Functions

Minagawa¹,

Koyama

2005

COC

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Various materials that show reversible changes in the rheological properties in response to external stimuli, especially electric and/or magnetic fields, have attracted attention because of their possible applications to devices of transformation of electric/magnetic stimulus into mechanical (passive) force. These materials are called electrorheological (ER), magnetorheological (MR), and electromagnetorheological (EMR) materials. The field-responsive properties are regarded as 'rheological functions' induced by the field, which characterize these materials. The ER/MR materials can be classified into some types, i.e. suspensions, homogeneous or heterogeneous liquids, elastomers/gels, etc. according to the rheological characteristics in the absence and presence of the electric/magnetic fields. For each type, the field-induced rheological properties are briefly summarized, followed by some topics on the material preparation, stimuli-induced functions, and/or practical applications are exemplified. The materials chemistry, especially for organic/polymer materials, are mainly focused on here.

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Electrorheological properties of a mixture of two immiscible fluids having the same viscosity

Cited by 11 publications

References 7 publications

Synthesis, characterization, and partial hydrolysis of polyisoprene‐co‐poly(tert‐butyl methacrylate) and electrorheological properties of its suspensions

Synthesis, characterization, and partial hydrolysis of polyisoprene‐co‐poly(tert‐butyl methacrylate) and electrorheological properties of its suspensions

Three-dimensional observation of an immiscible polymer blend subjected to a step electric field under shear flow

Electro- and Magneto-Rheological Materials: Stimuli-Induced Rheological Functions

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