Facile synthesis and characterization of poly(dialkoxy-p-phenylene 1,3,4-oxadiazole-alt-phenylene 1,3,4-oxadiazole)s

Poly(dialkoxyphenylene 1,3,4-oxadiazole)s were conveniently synthesized to compare their material properties of solvent solubility, thermal stability and molecular alignment with respect to alkyl chain length and meta/para-phenylene structure. All prepared polymers exhibited good solubility in co-solvents containing various volume levels of chloroform to trifluoroacetic acid. Meta-polymers showed slightly better solubility than para-polymers. All polymers produced were thermally stable up to 320 degrees C. Photoluminescence of polymer films was observed with blue light emission at around 450 nm. X-ray diffraction patterns of all polymers indicated that they were composed of stacked molecular sheets with the same layer-to-layer distance of 3.4 angstrom. However, side chain-to-side chain and main chain-to-main distances within the layers increased with increasing alkyl chain lengths. The meta-polymer chains were separated more than the para-polymer chains.