| Abstract
| - A study has been performed of the manner in which two structural features of poly(olefinsulfone)s, helical backbones and calamitic side chains, create order in films. For this purpose copolymerswere prepared with one (polymer I) or two (polymer III) cyanobiphenyls per residue, and terpolymerswere prepared with both such residues diluted to below the 5% level within an otherwise poly(eicosenesulfone) chain (respectively, polymers II and IV). The polymers all have ordered phases according toX-ray powder diffraction studies on samples cooled from the melt, a layer spacing of about 45 Å beingdetected in the films as in the bulk. Those polymers with mainly eicosene sulfone residues had crystallinephases with large domains, the layers deriving from the helical backbones alone, the smectic A phasesof the parent poly(eicosene sulfone) being either suppressed or reduced in extent by the presence of thearomatic moieties, which were almost randomly orientated. Those with one or two cyanobiphenyls perresidue were liquid crystalline. In the latter the layer spacing derives from both backbone and side chainsand is reduced when the residues bear a second mesogen as a consequence of a constraining effect fromthe stiff backbone, as a novel model predicts. The spacers give rise to a glass transition and segregatethe planes in which the stiff backbones are assembled from the regions in which the aromatic groupsaggregate on account of the strong π−π* interactions. Amorphous and optically isotropic spun cast filmsof these polymers became ordered on cooling from the melt or just on annealing, with the order, asdetermined by studies on the optical properties, being homeotropic for the aromatics and being planarfor the backbones in a monodomain. For this arrangement we introduce the term homeo-planar smectic.Order parameters as high as 0.63 were measured for polymer I, from a clear film. The cyanobiphenylchromophores formed H aggregates, with blue shifts in absorption and red shifts in fluoresence, and alittle surprisingly these resulted in a circular dichroism, detectable when the films were inspected at anangle of 45° to the normal.
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