A Novel Enhancement of Nano Structure by Organic Acid Dopants in Emulsion Polymerization of Poly(o-toluidine)

A simple, more facile and green approach for the synthesis of poly(o-toluidine) (POT) has been described, by using oxidative emulsion polymerization in a heterogeneous phase by using ammonium persulfate as an oxidant and organic acids as dopant, acids used such as tartaric, oxalic and citric. The effect or influence of these dopants on conductivity, morphology of the nano structure of POT and physical properties are well studied and found that it depends on the nature and type of the functional organic acid dopants. By using this synthetic approach we have obtained POT nanostructures of uniform granular morphology, with average 40–100 nm particle size doped with oxalic or citric acid, whereas in tartaric acid doped POT fibrilar morphology with 40–60 nm size nano fibers was ascertained. These compounds were characterized by UV-Visible, FT-IR, SEM, and XRD. Electrical conductivity studies of these materials were also carried out and found increase in conductivity with citric acid and oxalic acid doped POT as compared to the tartaric acid. XRD studies showed partial crystalline nature of tartaric acid doped POT polymer as compared to others. By using this emulsion process, POT nanostructure formed with 60–100 nm diameter size having high yield, conductivity, and improved solubility in organic solvents in the emeraldine salt phase of polymer (confirmed by the presence of characteristic peaks at 420 nm and ∼800–850 nm). The influences of reaction conditions, e.g. monomer, acid concentration on the physico-chemical properties were also investigated.