Synthesis of polydiphenylamine with tunable size and shape via emulsion polymerization

The emulsion polymerization process was used in the synthesis of polydiphenylamine (PDPA) to obtain new morphologies, and the effects of surfactant types - anionic, cationic, non-ionic - and surfactant concentrations were investigated with the roles of a template and a dopant. Scanning electron microscopy images indicated different PDPA morphologies depending on the surfactant type. The new morphological structures of the obtained PDPA were leaf-like, coral-reef-like and red-blood-cell-like, which have not been synthesized or seen before. The agglomeration of each nanoparticle is in the range of 50 nm to 500 nm depending on the surfactant type. The structure characterizations carried out by Fourier transform infrared spectroscopy, X-ray diffractometry and UV-visible spectroscopy confirm the incorporation of surfactant in the PDPA. The electrical conductivity values of the PDPA with surfactants are higher than that without a surfactant by four orders of magnitude and are consistent with the resultant smaller particle sizes and narrower optical band gap as calculated from UV-visible data. To induce higher electrical conductivity of PDPA, various dopants were used. However, the thermal stability of the PDPA is lower than that of conventional microscopic PDPA (cPDPA) due to the larger surface area of PDPA which can decompose more easily. (c) 2014 Society of Chemical Industry