Poly(o-methylaniline) (poly-o-toluidine, PTOL) was synthesized by chemical oxidation of o-toluidine with ammonium peroxydisulfate in an aqueous 1.0 mol L-1 HCl solution. The progress of polymerization was followed by measuring the open-circuit potential (OCP) of a Pt electrode immersed in the reaction medium with the polymerization time. The chemical synthesis of PTOL was carried out at different monomer:oxidant (M:O) molar ratios (4:1, 2:1, 1.5:1, 1:1, and 0.66:1), and the products obtained were characterized by infrared spectroscopy, gel permeation chromatography, and X-ray diffraction. The molecular weight and percentage of crystallinity of PTOL are higher for samples synthesized in an excess of the monomer, i.e. at higher M:O ratios. However, the yield of PTOL prepared at higher M:O ratios is considerably low, in particular at a 4:1 M:O ratio, which is the M:O ratio most commonly used in the literature to synthesize polyaniline and its derivatives.
Copolymerization of aniline and o-toluidine is achieved by chemical oxidative polymerization with equal molar ratio of monomers in the presence of hydrochloric acid and ammonium persulphate as an oxidant. The copolymer found to be more soluble in polar solvents such as NMP, DMF and DMSO. FTIR spectroscopy confirms the copolymer chemical structure. UV spectroscopy shows π to π* transition and excitonic transition of the copolymer film. The copolymer is doped with camphorsulfonic acid (CSA) in m-cresol and then zinc oxide nanoparticles are dispersed into the copolymer and spin coated on to a glass plate. The scanning electron microscope image shows the morphology of the copolymer matrix. X-ray Diffraction shows the characteristic peaks of CSA and zinc oxide. EDAX analysis confirms the presence of CSA and zinc oxide. The dispersion of zinc oxide nanoparticles show quenching property of photoluminescence indicating that the copolymer can be used in the opto-electronics.