Liquid Crystals & Related Compounds

來源：Seebio.cn作者：西寶生物人氣：-發表時間：2012-03-12 09:27:57【大中小】

Liquid crystals possess properties of both the liquid and solid phases, which results in the characteristic fluidity and optical birefringence (anisotropy) properties. Generally, the liquid crystal molecules consist of long chain moiety, rigid core and readily polarized functional groups. In some instances, they may form into plate shapes. In the liquid crystal state, the molecules are constrained to rotate, and line up into a regular array. Depending on how these molecules are arranged, the liquid crystal phases are classified as nematic, smectic or cholesteric phases. The regularity of these molecular arrangement is reflected in the anisotropic properties of permittivity and refractive index. Therefore, it is possible to control the optical property of the liquid crystal by changing the molecular arrangement electrically. The response speed of liquid crystals is fast due to the fluidity properties, and phase changes can easily occur both electrically and by heating.¹⁾ The application of liquid crystals for display purposes originated in HeiMeir when he and his co-workers (1968) reported using light scattering in the display material.²⁾ Since then, Schiff base³⁾ and azoxybenzene types⁴⁾ were also developed; both have shown liquid crystalline state at room temperature. These developments have fundamentally contributed to today's prosperity within the liquid crystal industry. Some related compounds are shown as follows.