Investigation of electrorheological properties of some polianiline derivatives

Electrorheological (ER) fluids are unique electroactive materials that exhibitfascinating change in rheological and electrical properties in the presence of anelectric field. In the present study, various polyaniline (PAn) derivatives such aspoli(o-toluidine) (POT), poli(2-ethylaniline) (P2EAn), poli(N-methylaniline)(PNMAn) and poli(N-ethylaniline) (PNEAn) were chemically synthesized,characterized and examined for their ER properties at a series of concentrations(c = 5-25%, m/m). The synthesized polymers were characterized by FTIRspectroscopy, magnetic susceptibility and dielectric measurements. It was foundthat POT has the highest conductivity with a value of 6.87x10-5 Scm-1, and P2EAnhas the lowest with 1.01x10-5 Scm-1, among the polymer synthesized. Formation ofpolymers was supported by FTIR analyses. Sedimentation stabilities of thesuspensions that prepared in silicone oil were determined. ER properties of thesesuspensions were investigated under various dc. electric fields, shear rates andshear stresses. Furthermore, ER efficiency of the suspensions and effect oftemperature and frequency on to ER activity were also studied.