Electrorheological fluids are special viscous liquids, that are characterized by their
ability to undergo significant changes in their mechanical properties when an electric
field is applied. This property can be exploited in technological applications,
e.g. actuators, clutches, shock absorbers, and rehabilitation equipment to name a
few. Winslow [131] is credited for the first observation of the behaviour of electrorheological
fluids in 1949. Since then great strides have been made to overcome the
impediments of early electrorheological fluids, as the abrasive nature and the instability
of the suspension and the enormous voltage requirements that are necessary for
a significant change in the material properties. Nowadays existing electrorheological
fluids, which make the above mentioned devices possible, are the result of intensive
efforts to manufacture materials without these impediments.