The structure and conformations of comb-shaped LC poly(methacrylates) with a varied length of an alkoxy substituent of a phenylbenzoate mesogenic group in isotropic, nematic, and smectic phases were studied by small-angle neutron scattering. The radii of gyration of a polymer chain in direction parallel and perpendicular to the director of a liquid crystal R∥ and R⊥ were measured. The anisotropy of the polymer chain shape in the nematic and smectic phases was found to be R⊥/R∥ ∼ 1.4 and R⊥/R∥ ∼ ·2.7, respectively, thereby indicating the oblate conformation of macromolecules. It was demonstrated that the radii of gyration of the polymer in the smectic phase depends on the degree of polymerization z = 42-406 through the following analytical dependence R⊥ = (0.78 ± 0.04)z(0.59 ± 0.06) and R∥ = (1.5 ± 0.4)z(0.3 ± 0.08). It was demonstrated for the first time that the anisotropy of a polymer coil increases with the increasing molecular mass of the polymers.
|Number of pages||11|
|Journal||Polymer Science Series A|
|Publication status||Published - 1 Jan 1998|