The viscosity of certain fluids can be reversibly changed by an applied electric field. This kind of fluid is called an ER fluid. A liquid crystal is known as one of the typical ER fluids. The molecular long axis is arranged perpendicular to the shearing direction by an electric field, as a consequence, the viscosity increases. However, the turn-off process is governed by only the shearing. As a result, the response time of this process is still long. To improve the response time, dual frequency liquid crystals (DFLCs) were used in this study. It is possible to align the DFLC molecules along or perpendicularly to the electric field direction by varying the AC frequency. In this study, the relationship between the dielectric characteristic and the ER effect has been discussed.
