Electro-optic effect in nematic liquid crystals aligned with conductive polymer

摘要

The influence of the ionic contribution to electro-optic effect in nematic liquid crystals aligned with conducting polymers was investigated. The study has been carried out on symmetric cells filled with nematic liquid crystal 5CB having positive dielectric anisotropy. Planar alignment of the nematic director has been imposed using unidirectional rubbed conducting polymer substrates, namely polypyrrole (PPy) doped with different types of ions. Employing a typical experimental set-up, the intensities of linearly polarized He-Ne light beams, transmitted through each cell when submitted to an external electrical excitation, were measured. Fast electro-optic response times measured at switching off the electric field are probably related to the accumulated charge distributions at nematic-conducting polymer interface.