ABSTRACT
We are all familiar with the three states of matter: gases, liquids and solids. In the 19th century the liquid crystal state was discovered [1, 2]; this can be considered as the fourth state of matter [3]. The essential features and properties of liquid crystal phases and their relation to molecular structure are discussed here. Liquid crystals are encountered in liquid crystal displays (LCDs) in digital watches and other electronic equipment. Such applications are also considered later in this section. Surfactants and lipids form various types of liquid crystal phase but this is discussed in section C2.3. This section focuses on low-molecular-weight liquid crystals, polymer liquid crystals being discussed in the previous section.
