AC electric field induced flow and helix unwinding in focal conic texture of smectic C* liquid crystal

A thin (∼10 μm) focal conic texture of DOBAMBC in its SmC * phase is submitted to an AC electric field. Above a field threshold, a DC plug flow of the texture normal to the layers is observed. It always originates from the focus of the ellipses towards their centre and extends to the entire focal domain. At higher field, the associated viscous shear unwinds the helical texture. The flow thresholds is explained by the build up at the focus of a DC electric pressure, from the action of the AC field on AC space charges, generated by conductivity anisotropy Etude sur le DOBAMBC. Observation d'un ecoulement permanent bouchon au-dela d'un certain seuil