Yield stress analysis of electrorheological suspensions containing core–shell structured anisotropic poly(methyl methacrylate) microparticles

Abstract

An electrorheological (ER) model (Seo-Seo model) was applied to the yield stress analysis of the electrorheological fluids containing core-shell structured, snowman-like anisotropic poly(methyl methacrylate) micro particles. The model predictions were compared with the experimental data, to reveal a good agreement with the shear stress behavior, both quantitatively and qualitatively. The obtained static yield stress was compared with the dynamic yield stress calculated by the CCJ model. The analysis results indicated that static yield stress was higher than the dynamic yield stress. The master curve describing the apparent viscosity was obtained by appropriate scaling of both axes showing that a combination of dimensional analysis and flow curve analysis using the Seo-Seo model yielded a precise description of an ER fluid's rheological behavior.

Core–shell-structured Fe3O4 nanocomposite particles for high-performance/stable magnetorheological fluids: preparation and characteristics

“…Choi et al [36] [26]. The density of the Fe 3 O 4 -PPy core-shell microspheres was reduced to 2.24 g cm −3 , compared to 4.08 g cm −3 of the Fe 3 O 4 particles.…”

“…In MR fluids, two yield stresses are defined: the static yield stress( sy ) and the dynamic yield stress (τ dy ) (Fig. 1) [22][23][24][25][26][27][28][29][30][31][32]. The τ dy is obtained by extrapolating the shear stress curve versus the shear rate to the zero shear rate [1,22] The Bingham fluid model is the simplest model to fit the yield flow behavior; ) MR fluid.…”

“…where τ dy (E) is the dynamic yield stress when the applied electric field strength is E, and pl is E-dependent plastic viscosity, which approaches the suspension viscosity at a sufficiently high shear rate [1,26,27].…”

Helical Polymer Particles Derived from Aromatic Acetylenics and Prepared by Suspension Polymerization

“…They can be acquired in a variety of forms, for instance, multilayered, hollow, and core/shell structures . Meanwhile the preparation methods have advanced rapidly, from the traditional suspension polymerization, emulsion polymerization, and precipitation polymerization to new techniques such as dispersion polymerization, seeded polymerization, template approach, and self‐assembly . However, a majority of the polymeric particles created so far were derived from vinyl polymers.…”

“…They can be acquired in a variety of forms, for instance, multilayered, [ 1 ] hollow, [ 2 ] and core/ shell structures. [ 3 ] Meanwhile the preparation methods have advanced rapidly, from the traditional suspension polymerization, [ 4 ] emulsion polymerization, [ 5 ] and precipitation polymerization [ 6 ] to new techniques such as dispersion polymerization, [ 7 ] seeded polymerization, [ 8 ] template approach, [ 9 ] and self-assembly. [10][11][12] However, particles constructed by substituted polyacetylenes usually show interesting optical activity, due to the helical structures of predominant helicity adopted by substituted polyacetylene chains.…”