Solution,thermal and optical properties of novel poly(pyridinium salt)s derived from conjugated pyridine diamines

Several novel poly(pyridinium salt)s with heterocyclic pyridine moieties in their backbones with tosylate and triflimide counterions were prepared by either ring‐transmutation polymerization reaction of phenylated‐bis(pyrylium tosylate) with isomeric pyridine diamines of 4‐phenyl‐2,6‐bis(4‐aminophenyl)pyridine in dimethyl sulfoxide (DMSO) for 48 h at 130–140 °C or by metathesis reaction of the respective tosylate polymers with lithium triflimide in DMSO at about 60 °C. Their chemical structures were characterized by FTIR, ¹H, ¹³C NMR spectroscopy, and elemental analysis. Their number‐average molecular weights (M_n) were in the range of 8,000–51,000 and their polydispersities in the range of 1.18–2.13 as determined by gel permeation chromatography. They had excellent thermal stabilities of 340–458 °C and high glass transition temperatures >200 °C. As they showed good solubilities in common organic solvents, their solution properties were also characterized for their lyotropic liquid‐crystalline properties with polarizing optical microscopy (POM) studies. Their photoluminescent properties were examined by using a spectrofluorometer in both solution and solid states. Their quantum yields were rather low, which were in the range of 1.3–2.0%. Additionally, hand‐drawn fibers from the melts were examined to determine their morphologies with a number of microscopic techniques including POM, scanning electron microscopy, and transmission electron microscopy. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2010