TIT# Investigation of Molecular Order and Phase Transitions of Smectic
     Poly(ester imide)s by Means of Small-Angle X-ray Scattering
AUT# Wutz, Christoph; Stribeck, Norbert; Gieseler, Dagmar
SOU# Coll. Polym. Sci. (2000), 278, 1061-1069
LOC# xv048
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ABS# The molecular order and phase transitions of two smectic poly(ester
     imide)s based on aminobenzoic acid trimellitimide (PEI_1), resp.
     aminocinnamic acid trimellitimide (PEI_2) and $\alpha$,$\omega$-
     dihydroxydodecane were investigated by X-ray scattering. During cooling,
     the polymers pass through monotropic smectic LC-phases ($S_A$, $S_C$),
     which transform into higher-ordered smectic-crystalline phases
     ($S_E$, $S_H$). The smectic layer structure of about $3 nm$ gives rise
     to a sharp reflection at $2\theta \about 3^o$. Peak shape analysis and
     analysis of the interface distribution functions (IDF) revealed
     long-range longitudinal correlation. The development of a broad reflection
     in the small-angle X-ray scattering (SAXS, $2\theta \lt 1^o$) indicates
     the formation of a lamellar two-phase system. The long period changes
     reversibly between 10 and 30 nm with increasing temperature. The
     crystalline lamellae comprise a number of smectic-crystalline layers
     with packed mesogens, wile the noncrystalline interlamellar regions
     keep their smectic LC order. In the metastable $S_B$ phase, formed
     during annealing of quenched PEI_1, the diffuse SAXS indicates a random
     distribution of small, probably fringed crystals with hexagonally
     packed mesogens. In the lamellar $S_E$ and $S_H§ phase, tie-molecules
     play an important rol, but chain folding cannot be excluded.