Spontaneous polarisation due to flexoelectric effect in liquid crystalline elastomers prepared by cross-linking under splay distortion

Flexoelectric polarisation in liquid crystalline elastomers with wedge-shaped mesogens was investigated. Flexoelectric polarisation was fixed in the elastomers that were cross-linked under uniaxial deformation with splay distortion. X-ray diffractometry revealed that the orientational order partially remained at about S = 0.2 even in the temperature region of the isotropic phase designated tentatively as the pseudo-isotropic phase. The electric charge caused by polarisation due to the flexoelectric effect was estimated to be -809 pC/mm(2) in the splay distorted liquid crystalline elastomers, whereas almost no electric charge was detected in the uniaxially and uniformly aligned elastomers. We tentatively conclude that the macroscopic polarisation due to flexoelectric effect emerged and was fixed in the liquid crystalline elastomers by cross-linking under splay distortion.