Electric-field-induced polar order in the uniaxial smectic phase of an asymmetric bent-shaped liquid crystal

Abstract

In addition to symmetric bent-shaped molecules, asymmetric ones have been attracting considerable attention because of their characteristic mesophases. Here we report the evaluation of the polar structure of an asymmetric bent-shaped molecule using second-harmonic generation (SHG) experiments. SHG signal was observed under a triangular electric field in the smectic temperature range. SHG signal increased with increasing the electric field and did not saturate even under a high field. These experimental results imply the following orientational change; The molecules (dipoles) freely rotate about their long axes parallel to the layer normal in the absence of a field, and electric-field-induced dipole reorientation occurs against thermal agitation.