Investigation of electrorheological properties of polyindole/polyethylene composite

In this study, electrorheological (ER) properties of conducting polyindole/polyethylene (PIN/PE) composites having five different compositions were investigated and results obtained are compared with homopolyindole (PIN). The particle sizes of the composites were determined by dynamic light scattering method. Conductivities of these composites were measured and dielectric properties were determined. Suspensions of PIN/PE composites were prepared in a silicone oil (SO), at several volume fractions ( ? = 5?25%) and their sedimentation stabilities were determined. Then the effects of dispersed particle volume fraction, shear rate, external electric field strength, frequency and temperature onto ER activities of suspensions were investigated. The flow times of these suspensions at various DC electric field strengths were measured. Further, creep tests were applied to the composite suspensions and reversible viscoelastic deformations observed. The most suitable working conditions for the composites were determined to be ? = 25% volume fraction, = 0.2 s-1 shear rate, T = 25 ? C temperature. The best ER results were obtained with the composite coded K5 (containing 89% PIN, 11% PE).