ER fluid based on inorganic/polymer blend particles and its adaptive viscoelastic properties

Electrorheological fluid (ERF) is one of the most favorite actuator materia ls used in smart materials and structures due to its fast, reversible, cont rollable and continuous change of rheological properties. In the present pa per, a new kind of ERF based on silica carried lithium salt of phenolic pol ymer particles dispersed in silicon oil is developed. This kind of ERF perf orms good ER activity. The yield stress is about 1900Pa while the electric field strength is 3.2 kV mm(-1) and the current density is less than 8 muA cm(-2). The viscoelastic properties of this ERF are investigated experiment ally by both the steady shear and dynamic test while the electric field str ength range is 0-5 kV mm(-1). ERF behaves adaptive viscoelasticity while th e control parameter is the electric field strength. External electric field can change ERF's shear modulus effectively. With an external electric fiel d, ERF shows not only linear viscoelastic properties but also non-linear vi scoelastic properties. The viscoelastic parameters such as creep compliance and shear modulus depend on external electric field strength, the amplitud e of shear force, as well as the shear force frequency. (C) 2001 Elsevier S cience B.V. All rights reserved.