Structure and Properties of Side Group Thermotropic Liquid Crystal Polymers

Abstract

Abstract The liquid crystalline behavior of side‐chain liquid crystal polymers (LCPs) resembles that of low‐molecular‐weight liquid crystals, because it is mainly dependent on interactions between mesogenic side groups. The flexibility of the polymer backbone and the length of the spacer are important factors determining the physical properties because the dynamic properties of the mesogenic groups are influenced by nonmesogenic parts of both the polymer backbone and the spacer chain. The orientational order of the mesogenic groups and the thermal stability of the liquid crystalline states increase when the side‐chain LCPs have a highly flexible polymer backbone and a long spacer. The influence of these structures on the physical properties of the side‐chain LCPs is examined in this chapter. The thermal, mechanical, optical, electric, and electronic properties of side‐chain LCPs depend on the orientational order and molecular dynamics properties of the side‐chain LCPs. The dielectric properties and electro‐optical effects provide important information about the dynamics and the orientational order. These properties are mainly determined by the characters of the mesogenic side groups, and in the side‐chain LCPs, the mesogenic side groups are dominantly assembled into strongly coupled units through the influence of the polymer backbone. In this chapter, the structure and properties of the side‐chain LCPs are discussed. In particular, their phase transitions, dielectric properties, and ferroelectric response are revealed.