Anisotropic-network-stabilized ferroelectric gels for active matrix addressing

Ferroelectric gels have been produced by polymerization of liquid crystal (LC) diacrylates in mixtures of nonreactive molecules showing the ferroelectric LC (FLC) phase. Within the gels, the orientational, optical, and electrical properties of the nonreactive molecules are to a large extent dominated by the polymer network. For this reason the gels are also referred to as anisotropic-network-stabilized FLC. In this publication gels with homogeneous and hybrid orientations are described. Network molecules of various birefringences are used to show that the effective birefringence within the gels can be reduced. The extinction angle within the gels is also influenced by the anisotropy and the concentration of the network. The gels also show continuous switching over a broad range of voltages. The voltage range becomes broader and shifts to higher voltages with an increasing network concentration. This behavior of FLC gels makes them suitable for the production of grey levels in display applications. Using a transistor as an electronic switch for applying voltages it is shown that gels with homogeneous and hybrid orientations can give smooth transmission–voltage curves.