Electrosynthesis and characterization of poly methylene blue and its nanocomposite with ZnO nanoparticles

The poly methylene blue (PMB) films were deposited on ITO electrode by cyclic voltammetry. The fractal dimension of PMB films in the presence of counter ions was investigated. Theoretical calculations for methylene blue polymerization were carried out at density functional theory (DFT) level using the 6-31G(d,p) basis set for all atoms with Gaussian 03 program package. ZnO nanoparticles were dispersed into the polymer matrix via in situ electropolymerisation. Surface morphology of the composite film was studied by surface microscopy techniques (SEM). The presence of ZnO in the films was confirmed by EDS analysis. Furthermore experimental absorbance spectra of PMB/ZnO compared with results obtained from the Maxwell–Garnett theory (MGT) and the values of energy Eg of composite were determined as Eg1 = 3.3 eV, Eg2 = 2.7 eV and Eg3 = 1.7 eV, respectively. The results show that composite films are photosensitive and they can be used as photoluminescent materials in optoelectronic devices.