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Polymeric liquid crystals are basically the polymer versions of the monomers discussed in Section 1.1. A good account of polymeric liquid crystals may be found in [9]. There are three common types of polymers, as shown in Figure 1.9a–c, which are characterized by the degree of flexibility. The vinyl type (Figure 1.9a) is the most flexible, the Dupont Kevlar polymer (Figure 1.9b) is semirigid, and the polypeptide chain (Figure 1.9c) is the most rigid. Mesogenic (or liquid crystalline) polymers are classified in accordance with the molecular architectural arrangement of the mesogenic monomer. Main‐chain polymers are built by linking rigid mesogenic groups in a manner depicted schematically in Figure 1.10a; the link may be a direct bond or some flexible spacer. Liquid crystal side‐chain polymers are formed by pendant side attachment of mesogenic monomers to a conventional polymeric chain, as depicted in Figure 1.10b.

Figure 1.9. Three different types of polymeric liquid crystals: (a) vinyl type; (b) Kevlar polymer; (c) polypeptide chain.

Figure 1.10. Polymeric liquid crystals: (a) main chain; (b) side chain.