71 research outputs found
Poly(ester-ß-sulphide) from azoxybis(1,4-phenylene diacrylate and 2,2’-oxydiethanedithiol
The synthesis and chemical transformation of chiral liquid crystalline poly(ester ß-sulfide)s
Chiral liquid crystalline polymers. XI. Thermotropic behavior and chiroptical properties in solution of a new series of optically active poly(ester ß-sulphide)s
Liquid crystal poly(ß-aminoester)s. Thermotropic mesomorphism and degradability in solution
On the isotropic-anisotropic biphasic behavior of two side chain liquid-crystalline polyacrylates
Structure of the nematic mesophase with cybotactic groups in liquid-crystalline poly(urethane-ester)s
The results of a structural analysis by x-ray diffraction on fiber samples of the nematic mesophase with cybotactic groups of poly(urethane-ester) TDI-C2C6, TDI-C6C4, TDI-C6C6, TDI-C6C8, and TDI-C6C10 as prepared from various mesogenic alkylene di[4-(omega-hydroxyalkyloxy-4-oxybenzoyl)oxybenzoate]s (CmCn; m = 2 or 6 and n = 4, 6, 8, or 10) and 2,4-toluenediisocyanate (TDI) are reported. Evidence is provided for the existence of two different molecular orderings within the nematic phases with cybotactic groups, to which different internal degrees of correlation correspond. The average dimension of the cybotactic clusters along the director is comprised between similar to 260 and similar to 560 Angstrom, whereas the average dimension perpendicular to the director ranges from similar to 130 to similar to 270 Angstrom. Accordingly, the cybotactic clusters present an asymmetrical ellipsoidal-like shape. On the other hand, the correlation length within the nematic liquid crystal surrounding the cybotactic clusters and along the director is between 38 and 45 Angstrom. These values are of the order of the molecular length. These findings highlight the multidomain nature of the mesophase consisting of large and asymmetric clusters surrounded by a conventional nematic endowed with a very low correlation degree
Dynamic-mechanical properties of amorphous and semicrystalline side-chain polymeric liquid crystals
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