Crystalline features poly concentration

Various forms of doped PANI are discussed by Moon el al. [300]. PANls doped with Cl and CIO4" are synthesized in powder form, and HSO4 -doped PANI is obtained by dissolving a Cl -doped form in concentrated H2SO4 and allowing H2O from the atmosphere to precipitate it from this solution. The Cr-doped form is found to be the most crystalline one and to have the most detailed diffraction pattern. The diffraction from the other preparations is similar a structural analysis has not been carried out by the authors. De-doping in aqueous NH OH in this case leads to PANI base with distinct crystallinity, in contrast to results from earlier studies. The similarity between the molecular stnicture of emeraldine base and that of poly(pap-a-phenylene sulphide) and poly(para-pheny-lene oxide) is inferred from common features of the diffraction patterns of the three polymers. 

Droscher et al prepared chemically similar poly(oxymethylene)-based copolymers (with 1,3-dioxalane, 1,3-dioxane, 1,3-dioxepane and 1,3,6-trioxocane as respective comonomers) which were of extended crystal form and presumed to be completely crystalline. For this series of copolymers, the melting temperature-composition relation at low co-unit content depended on the chemical nature of the comonomer used. The characteristic curve observed by Inoue " was not found. It was presumed that an appreciable concentration of co-units enter the lattice. An interesting feature developed at higher co-unit concentration. Depending on the co-unit type, the melting temperatures became invariant with composition, while the normal poly(oxymethylene) unit cell was maintained. 

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