How are LSP classified?
Thermotropic LSP shows different phases depending on the temperature these are classified as-
Nematic:
It is the most common LC phase; nematic is a geek word meaning thread. In nematic phase, the calamity or shaped organic molecules have no positional order, but they self-align to have a long-range directional order with their long axes roughly parallel. Thus, the molecules are free to glow and their centre of mass positions is randomly distributed as in a liquid, but still maintains their long-range directional order. Nematics have fluidity similar or electric field. Aligned nematics have the option properties of uniaxial crystal and thus can be used in liquid crystal displays (LCD).
Semitic:
It is observed at a lower temperature than the nematic, it forms well-defined layers that slide over another like that of soap. The smectics are positionally ordered along one direction. These phases are liquid like within the layers. Threes are many different smectic phases, all characterized by different types and degrees of positional and orientation order.
Cholesteric:
It is the nematic phase it shows chirality or handiness this phase is called the cholesterol phase because it was first observed for cholesterol derivations. Only chiral molecules having no internal panes of symmetry give rise to such phase. It shows a twisting of the molecules perpendicular to the director, with the molecule axis parallel to the director, the finite twist angle between adjacent molecules is due to their asymmetric packing, which results in longer chiral order the chirality induces a finite azimuthal twist from one to the next producing a spiral twisting of the molecular axis along the layer normal.