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.

摘要

The synthesis of hemiphasmidic monomers 4-(3,4,5-tris(S(-)-2-methylbutan-1-yloxybenzoyloxy -4'-(p-allyloxybenzoyloxy)biphenyl (4), 4-3,4,5-tris(n-pentan-1-yloxy)benzoyloxy-4'-(p- allyloxybenzoyloxy)biphenyl (15), and 4-(3,4,5-tris(n-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.