Liquid Crystalline Polymers: A Novel State of Material

Liquid crystals were discovered about ninety years ago. The Austrian botonist Reinitzer [1] observed that cholesteryl benzoate has two sharp melting points at ∼145 and 179°C. At 145°C the solid crystalline material changed to a hazy anisotropic liquid which at 179°C became a clear, transparent, and isotropic phase. The nature of cholesteryl benzoate in the temperature region of 145–179°C was called the liquid crystalline (LC) state or, more precisely, the mesomorphic state. Materials having the tendency above the melting temperature (Tm) of simultaneously combining the features of liquid (i.e., flow properties) and crystalline bodies (i.e., anisotropy) were called liquid crystals [2] or mesomorphic substances [3].