Liquid Crystals: Fundamentals by Shri Singh (Repost)

Although liquid crystals were discovered as an interesting phenomenon at the end of the 19th century, it took nearly 30 years of research to establish their true identity. Georges Friedel in the 1920's was responsible for recognising that liquid crystals are indeed a new state of matter that is intermediate in structure and molecular organisation between the amorphous liquid state and the solid crystalline state. After a further 80 years of research, the number of known liquid crystal phases has increased from the original two, named by Friedel as nematic and smectic, to between 15 and 20 mesophases. The discovery of liquid crystals coincided with a period of rapid expansion in terms of the physical techniques available to study materials. This, together with great advances in the theory of condensed matter, made liquid crystals an exciting area for scientific research. It attracted experimental and theoretical physicists, applied mathematicians and synthetic chemists, all of whom have contributed to the foundations of the science of liquid crystals. A multidisciplinary approach has been a characteristic of studies in liquid crystals, and those working in the area are expected to have some familiarity with the chemical constitution of the materials and their properties, together with a knowledge of the physics of the phenomena which they exhibit.