Electro-rheological polymers

Abstract

Smart fluids in the form of electro-rheological (ER) fluids are among the most spectacular of the smart materials. ER fluids are typically suspensions of semiconducting, solid particles dispersed in an insulating carrier liquid, which show a dramatic increase in flow resistance when an external electric field is applied. This reversible and rapid change in flow properties has potential applications in many electronically controlled mechanical devices. This article gives a short overview of the field of ER materials and their basic properties. Current and future developments with particular attention to electrorheological polymers have been reviewed.

Aeroelastic analysis and active flutter suppression of an electro-rheological sandwich cylindrical panel under yawed supersonic flow

“…Also, the variations of the total works done by the external transverse distributed force, f (x, θ, t), the aerodynamic pressure load, P , and the core material damping force, along with the total kinetic and strain energies of the composite panel, are respectively written as [19,22]: (2) xz +γ (2) θ z δγ (2) …”

“…Such structures function on modification of the system stiffness and damping by governing the rheological response of ER material via regulation of the intensity of the imposed electric field. In particular, Electro-Rheological Fluids (ERFs), which incorporate suspensions of micro-scaled polarizable solid particles dispersed in a non-conducting base carrier liquid, exhibit a dramatic increase in flow resistance (effective viscosity) as the electric field increases [2]. When the electric field strength is high enough, the electro-rheological fluid can rigidify and convert to a solid-like state.…”

Review of Paste Explosives (PEX)

“…ER fluids are typically suspensions of semiconducting, solid particles dispersed in an insulating carrier liquid. In order to make an MR fluid the electric polarization (for ER fluids) is replaced by a magnetic polarization 32. These fluids require a material to be suspended in another material, e.g.…”

“…The major consideration for both of these fluids is that the densities of dispersed phase and the dispersant should be similar to prevent sedimentation. Of the papers reviewed in Akhavan’s paper 32, the fraction of particles suspended in the fluid was up to a maximum of 40 %. This is some way short of the 65 % required for a PEX.…”

The electrorheological effect for polyhedral silsesquioxane cage structures with cyanopropyl functional groups

“…silica, titania) [5] and polymeric materials (e.g. Polyaniline) [6]. Additionally nanomaterials have been investigated as well.…”