Smectic-C and Ferroelectric Liquid Crystals

Smectic-C, or ferroelectric liquid crystals, which possess nonzero spontaneous polarization P, may be classified into two categories. In the case of unwound SmC [Pg.88]

In helically modulated SmC liquid crystals, the bulk polarization is vanishingly small. The helicity can be unwound by an external field applied parallel to the smectic layers. It can also be unwound by surface effects if the samples are sufficiently thin (thickness pitch), leading to the so-called surface-stabilized ferroelectric liquid crystal (SSFLC) with a nonvanishing macroscopic polarization. [Pg.89]

Both the tilt angle 0 and the spontaneous polarization P decrease in magnitude as the temperature of the system is increased. Above a critical temperature Pc phase transition to the untilted SmA phase takes place. [Pg.89]

Various optical effects arise as a result of the presence of the spontaneous polarization. Electro-optical effects will be discussed in Chapter 6. In this section our attention will be focused on their basic physical and optical properties. [Pg.89]

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