Materials and mechanisms in electrorheology

The Effect of Polyaniline Content Deposited on Silica Gel Particles on the Electrorheology of Silicone-Oil Suspensions

“…The results obtained so far indicate that an appreciable ER effect occurs when the relaxation frequency, at which the relative dielectric loss factor 1::" has a local maximum, is in the frequency range 10-10 5 Hz corresponding to the interfacial polarization [2,[26][27][28]. The magnitude of polarization depends on the difference of dielectric constants e' below and above this frequency value.…”

Field strength dependence of the high-frequency viscoelastic relaxation process in polyaniline/silicone oil electrorheological suspensions

“…In an ER system, in the absence of a field, the particles are randomly dispersed in suspension and the dynamic moduli generally exhibit liquid-like behavior such that G″ is significantly larger than G′ over the entire frequency range. On application of a field, the particles form strings or columns spanning the gap between the electrodes, as a result of interfacial polarization due to migration of charge carriers in the PANI particle [16]. As the electric field strength increases to a critical value, the ER fluid passes through a series of transformations [12].…”

Comparison of electrorheological characteristics obtained in two geometrical arrangements: Parallel plates and concentric cylinders

“…The formation of a chain-like structure occurs due to particle polarisation in the direction of an electric field. A number of studies of this mechanism have been summarized in several review papers (Block and Kelly [5], Jordan and Shaw [6], Block et al [7], Parthasarathy and Klingenberg [8], See [9], Hao [10,11], Sheng and Wen [12]). Most commercially available rheometers can be equipped with ER cells making full use of the functionality of the host instruments.…”