Surface stabilised ferroelectric

When suitably doped, MBF can form a surface-stabilised-ferroelectric smectic-C (SSFLC) structure. Using simple assumptions regarding core orientations, Binger and Hanna are able to place an upper limit on the SSFLC cone angle for MBF of 30°. 

Surface Stabilised Ferroelectric Super Twisted Nematic temperature (degrees centigrade)... 

We can answer the last question if consider a constraction of the so-called surface stabilised ferroelectric liquid crystal cell or simply SSFLC ceU [9]. Such SSFLC cell is only few micrometers thin and, due to anchoring of the director at the surfaces, the intrinsic helical stmcture of the SmC is unwound by boundaries but a high value of the spontaneous polarisation is conserved. The cell is con-stracted in a way to realise two stable states of the smectic C liquid crystal using its interaction with the surfaces of electrodes, see Fig. 13.6a. First of all, in the SSFLC cell, the so-called bookshelf geometry is assumed the smectic layers are vertical (like books) with their normal h parallel the z-axis. Then the director is free to rotate along the conical surface about the h axis as shown in Fig. 13.6b (Goldstone mode). It is important that, to have a bistability, the director should be properly... 

The switching of the director in the surface stabilised ferroelectric liquid crystal cells (SSFLC) [8] has briefly been discussed in Section 13.1.2. Due to its importance for ferroelectric liquid crystal displays we shall discuss this effect in more detail. The geometry of a planar cell of thickness d is shown in Fig. 13.1.2. Now, the helical structure is considered to be unwound. We are interested in the field and time behaviour of the director or c-director given by angle cp(r), and this process is considered to be independent of z and y- coordinates. The smectic C equilibrium tilt angle 9 is assumed constant. 

Thus it passes through the top polariser and the cell appears bright. Because the switching in both directions is driven by the interaction of the spontaneous polarisation with the electric field (rather than the interaction between an induced polarisation and the electric field or a relaxation process when the electric field is removed), these surface stabilised ferroelectric hquid crystal (SSFLC) displays are much faster than twisted nematic and birefringent displays. 

---