Flexible rodlike mesogens

Figure 3.9. Flexible rodlike mesogenic units proposed by Percec and coworkers.

Figure 2 Some molecular architectures of liquid crystalline polymers incorporating rodlike mesogens and flexible spacers. ...

The two main liquid-crystal polymorphs, nematic and smectic, of disc- and rodlike mesogens are compared in Fig. 5.134 to their ideal crystals. Possible flexible... 

Thermotropic liquid crystals are controlled by the melting temperature Tm and by the isotropic temperature TJ for the stability of mesophases. In certain cases, a glass temperature Tg rather than a melting temperature may be observed before the isotropic temperature 7 . The mesophases of thermotropic liquid-crystalline polymers are formed in pure compounds or in polymer melt. Their properties are essentially based upon rodlike mesogenic moieties polymerized together with small flexible chains, that is, the main-chain or side-chain polymers. 

Liquid Crystalline Polymers are an important class of polymeric materials because they may exhibit optical properties similar to low-molar-mass liquid crystals and high mechanical properties of polymers. These polymers are broadly classified based on their molecular architecture, i.e. attachment of the mesogen to the polymeric backbone, as main-chain liquid crystal polymers (i) or side-chain liquid crystal polymers (2). In main-chain liquid crystal polymers, mesogens are incorporated into the backbone. The mesogens may be of different shapes and sizes, and are usually rodlike or disklike. Such polymers have not been used for optoelectronic applications because it is very difficult to reorient these materials by electric field. Instead, these materials find applications that use their exceptional mechanical properties. Even side-chain liquid crystal polymers, whose mesogen is attached to the polymer backbone through a flexible spacer switch too slowly for... 

Uniform Main-Chain Mesogenicity Flexible, Wormlike, Rodlike... 

Figure 24 Phase tapping-mode images of individual supramolecular structures formed upon complexation of wedge-shaped mesogenes with a linear flexible chain. The shape of the structures depends on the degree of polymerization of the chain and degree of complexation x (a) spheres (b) semiflexible cylinders and (c) rodlike particles. ...

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