The electrorheological performance of polyaniline-based hybrid particles suspensions in silicone oil: influence of the dispersing medium viscosity

The potential of electrorheological (ER) suspensions based on polarizable particles in simple liquids relies on the particles arrangements which turn their quasi Newtonian behavior into gel-like. However, minor attention has been paid to the effect provoked by the liquid viscosity on the ease of orientation and assembly of the particles. With this aim, a study on the ER behavior, at 25 degrees C, of 1 wt% suspensions of polyaniline (PANI)-based hybrid particles (-graphene or -tungstene oxide) in silicone oil with varying viscosities (20, 50 and 100 cSt) was carried out. The electric field effect was higher for the PANI-graphene particles suspension in the less viscous silicone oil. However, two drawbacks were observed: (a) higher leakage current flows; and (b) reduced reversibility upon the electric field was turned off. The use of silicone oil with higher viscosity solved these issues.