X-ray diffraction by thermotropic main-chain polymers with side groups. II. semiflexible polyesters

Semiflexible thermotropic aromatic polyesters with lateral groups were aligned magnetically and mechanically in monodomains after separation into high-molecular-weight (polymer) and low-molecular-weight (oligomer) fractions. Based on the x-ray intensity distributions recorded for a series of seven different substituents in the arylsulfonyl substituted group, a novel smectic structure was determined for H, F, Cl, OCH₃, and CH₃ in the para position while a normal nematic alignment prevailed when it contained Br or NO₂.