Dynamic local-layer response of surface-stabilized ferroelectric liquid crystals to a high electric field by time-resolved x-ray microdiffraction.

Abstract

Time-resolved synchrotron x-ray microdiffraction measurements have directly revealed the dynamic local-layer response to the high electric field in a surface-stabilized ferroelectric liquid crystal. The irreversible layer transformation under the increasing electric field is found to consist of two stages; the initial vertical chevron structure transforms to the alternate vertical and horizontal chevrons and, with increasing field, the chevron angle decreases and the horizontal chevron structure develops. The time-resolved microdiffraction measurement has clarified the detailed reversible layer transformation between the mostly horizontal chevron at the high field and the so-called quasibookshelf at the low field during the ac field application. The transient layer response time is about 0.1-0.2 and 0.3-0.4 ms for falling and rising edges, respectively, and is slightly longer than the optical response time. The layer transformation is discussed in terms of electric torque and surface anchoring. The local-layer response in the antiferroelectric liquid crystal is also discussed for comparison.