Director/barycentric rotation in cholesteric droplets under temperature gradient

• DOI: 10.1039/c4sm00670d
• Publication Date: 2014-05-02T08:48:38Z
• Authors: Jun Yoshioka; Fumiya Ito; Yuto Suzuki; Hiroaki Takahashi; Hideaki Takizawa; Yuka Tabe
• Keywords: Temperature Gradient; Principal axis theorem; Chirality; Cholesteric liquid crystal; Heat current; Helix (gastropod)

When a chiral liquid crystal is given transport current, unidirectional molecular motion known to take place, which called the Lehmann effect. In this paper, we study mysterious heat-current-driven effect using two types of hemispherical cholesteric droplets polarizing, reflecting, confocal and fluorescent microscopies. Both droplets, coexisting with isotropic phase contacting on glass substrate, are characterized by concavo-convex modulated surface inside orientational helix. Further, only difference between them helical axis direction; i.e., one perpendicular other parallel substrate. Under temperature gradient droplet whose heat current exhibited pure director rotation, while that rotated independently as rigid body. rotational conversion efficiency from into angular velocity showed very different dependences chirality strength droplets' size, suggesting rotations may be driven independent torques origins. This first observation under exhibit modes, rotation barycentric motion, can switched each changing heat-current direction axis.