Shell-printed texture

The precursor 6 exhibits the enantiotropic nature of chiral nematic (N ), chiral smectic C (SmC ) and chiral smectic I (SmI ) phases. The shell-printed texture of the SmC phase and the rose-like texture of the SmI phase can be clearly seen in Figure 12.6. The thiophene monomers, M2 and M3, show enantiotropic N, SmA and SmC phases. The SmC phase is characteristic of ferroelectricity. The polymers show various mesophases. The phase transition temperatures are summarized in Table 12.4. PI shows an enantiotropic SmA phase. P2 shows enantiotropic SmA, SmC and SmB phases. The fan-shaped texture of the SmA phase and the striated fan-shaped texture of the SmC phase are shown in Figure 12.7. P3 shows an SmA phase in the heating process and SmA and SmX phases in the cooling process. XRD analysis suggests that the SmX phase of P3 might be a higher order smectic phase. 

Figure 12.6 Polarizing optical micrographs of compound 6. (a) Shell-printed texture of chiral smectic C (SmC ) phase at W4°C (b) rose-like texture of chiral smectic I (SmI ) phase at 91 °C. From H. Narihiro, X.-hA. Dai, H. Goto, K. Akagi, Synthesis and properties of polythienylene derivatives with fluorine-containing chiral liquid crystalline substituents (I), Mol. Cryst. Liq. Cryst, 365, 363-371 (2001), reprinted by permission of the publisher (Taylor Francis Ltd, http //www.tandf.co.uk/journals)...

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See also in sourсe #XX -- [ ]

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