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Liquid Crystalline Polymers Containing Mesogenic Units Based on Half- Disc and Rod-Like Moieties. 5. Side Chain Liquid Crystalline Polymethylsiloxanes Containing Hemiphasmidic Mesogens Based on 4-(3,4,5-Tris(alkan-1-yloxy) benzoyloxy)-4-(p-(propan-l-yloxy)benzoyloxy)biphenyl Groups
CASE WESTERN RESERVE UNIV CLEVELAND OH DEPT OF MACROMOLECULAR SCIENCE
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The synthesis of hemiphasmidic monomers 4-3,4,5-trisS--2- methylbutan-1-yloxybenzoyloxy -4-p-allyloxybenzoyloxybiphenyl 4, 4-3,4,5- trisn-pentan-1-yloxybenzoyloxy-4-p-allyloxybenzoyloxybiphenyl 15, and 4- 3,4,5-trisn-dodecan-1-yloxy benzoyloxy-4-p-allyloxybenzoyloxy biphenyl 16 and of the corresponding polymethylsiloxanes 17,18, and 19 is described. Both monomers and polymers were characterized by a combination of differential scanning calorimetry DSC, WAXS, SAXS, and thermal optical polarized microscopy. 15, 16, and 17 are crystalline. 17 exhibits an enantiotropic double layer smectic A or C mesophase. 18 displays a monotropic columnar hexagonal and an enantiotropic double layer smectic A or C mesophases. Due to its close proximity to the glass transition temperature, the columnar hexagonal phase of 18 is strongly kinetically controlled. 19 exhibits a very broad enantiotropic hexagonal columnar mesophase. The columns of the mesophases of 18 and 19 are generated by an elongated polymer backbone penetrating through the center of the column and tapered extended mesogens radiating out of it.
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