Hystersis Behaviors of Poly(Naphthalene Quinone) Radical Electrorheological Fluid

초록

As a potential electrorheological(ER) material, poly(naphthalene quinone) radical(PNQR) ER fluid was prepared, and its rheological behavior and hysteresis phenomenon were investigated. PNQR was synthesized by Friedel-Crafts acylation between naphthalene and phthalic anhydride, using zinc chloride as a catalyst at 256C. A Physica rheometer equipped with a high voltage generator was used to measure the rheolohical properties of the ER fluids, which were prepared by dispersing PNQR in silicone oil at several particle concentration. Shear stresses were observed to decrease as shear rate incrased in the region of slow deformation rate. It was further found that ER fluid showed different hysteresis behaviors according to the shear rate ranges; thixotropy was observed in the low shear rate region(0.007-0.5 1/s) and anti-thixotropy in the high shear rate region(0.5-1000 1/s). Controlled shear stress mode was also applied to observe similar behaviors.