Liquid crystals smectics

Initially smectic phases can be subdivided into the true liquid crystal smectics and the... 

ATGB and antiferroeleotric liquid crystal Smectic C liquid cyrstal... 

The FLCs or AFLCs mentioned above are liquid crystalline materials showing a chiral smectic C phase or related phases. Although nematic liquid crystal possesses only directional order, smectic liquid crystals shows layer structures or periodic order of the liquid crystalline molecular centres. In this respect, smectic liquid crystalline materials have more in common with crystalline materials than with nematic liquid crystalline materials. As a result, the alignment of smectic liquid crystal is quite different from that of nematic liquid crystals. Smectic liquid crystals show a large variety of defects because they possesses highly ordered structiu-es. Moreover, the layer structures are irreversibly destroyed by applying stress. This phenomenon poses a major problem for display applications. Therefore, several techniques to prevent the application of force to the liquid crystalline materials of FLC or AFLC devices have been proposed. 

R. Lucht and C. Bahr, Surface plasmon resonance study of the spreading of a liquid-crystal smectic-A droplet on a gold substrate, Phys. Rev. Lett.,... 

However in chiral tilted liquid crystal smectic phases, the polarization is driven by the tilt angle, and the phase transition will not necessarily be of second order. 

It should be mentioned that, for certain classes of liquid crystals (polymeric liquid crystals, smectic liquid crystals), the light scattering method allows the determination of the viscosity coefficients, whereas their measurement by means of mechanical methods is very difficult. 

They found that an asymmetric carbon atom and a dipole moment in the molecular structure lead to a liquid crystal smectic C phase in which the molecular long axes are tilted from the layer normal of the smectic phase. Hence, ferroelectricity was expressed. The ferroelectric behavior definitely was confirmed by various measurements, including the D-E hysteresis [2]. 

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