Synthesis and characterization of conductive polymer poly(p-phenylenevinylene) derivatives and investigation of their various properties

A modified Gilch polymerization method, with optimized synthesis procedures were utilized to prepare poly(para phenylenevinylene) (PPV) derivatives of differing symmetric and asymmetric alkoxyl substituents. Structural characterizations of the compounds were carried out by FT-IR, NMR, LC-MS, UV-Vis, photoluminescence spectroscopy and elemental analyses. 1H and 13C NMR and FT-IR spectra confirmed the structures of these polymers.1H NMR spectra of the symmetric PPV polymers gave aliphatic protons in region  0.84-4.15 ppm and aromatic protons in region  7.15-7.19 ppm. The symmetric polymers had number-average molecular weights and weight-average molecular weights of 12,780-22,230 and 35,150-79,770. The SEM photographs of all the PPV polymers showed that these polymers formed solid, uniform and homogeneous films. The HCl-doped films of the symmetric and asymmetric PPV polymers gave electrical conductivities in ranges 0.1847-0.4585 Scm-1 and 0.1518-0.3502 Scm-1, respectively. The emission energy values for the calculated band gaps were in the ranges of 2.16-2.12 eV and 2.17-2.13 eV for the symmetric and asymmetric polymers, respectively. The thermal behavior and heat changes of the all PPV polymers were monitored by TGA and DSC. The symmetric and asymmetric PPV polymers showed enthalpies 220.41-599.98 J/g and 245.97-515.24 J/g and entropies 0.567-1.754 J/goC and 0.736-1.435 J/goC, respectively.