A novel pre-shearing technique for measurement of the electrorheological effect of a side-chain liquid crystalline polysiloxane

A side- chain liquid crystalline polysiloxane derivative possessing mesogens was synthesized. The mesogens included a large dielectrically- anisotropic moiety. Phase transition behaviour was investigated and the electrorheological ( ER) effect of the polymer considered. No ER effect was observed in non- sheared polysiloxane derivative because of its high inherent viscosity. However, a large ER effect was observed after pre- shearing. Pre- shearing, i. e. shearing with a high shear rate before the measurements, arranges the terminal mesogens in the shearing direction. Furthermore, a dilution of the sample led to a larger ER effect exceeding 10 000 Pa. We thus were able to demonstrate a new approach for the appearance of the ER effect.