| Popis: |
Liquid crystals were discovered in 1888 but have been studied seriously during the past 20 years. The kinds of molecules that form liquid crystals on heating and by mixing two or more substances are explained. Properties of liquid crystals and related structural characteristics are summarized. The properties considered include optical characteristics, textures, and the role of water in lyotropic systems. The structures of nematic and smectic liquid crystals are explained and systemized. Determination of the tilt angle of the molecules in the smectic C compounds terephthal-bis-(4,n-butylaniline) (TBBA and its C5 and C6 homologs) is discussed. The molecular packings in the crystalline forms of three nematogenic compounds are explained. |
