Polypyrrole-Polyvinyl Alcohol Stable Nanodispersion: A Prospective Conducting Black Ink

Chemical polymerization of pyrrole within aqueous polyvinyl alcohol (PVA) solution gives rise to a nanodispersion with unique stability and monodispersity. The nanodispersion has shown uniform distribution of perfectly spherical similar to 110 nm polypyrrole particles (from transmission electron microscopy and dynamic light scattering) with high doping level (from UV-Vis analysis) and sufficient electrical conductivity (10(-3) S/cm). The dispersion with optimum stability and conductivity was subjected to viscoelastic studies. The viscosity of the system was adjusted by dilution with water and shear thinning (under steady shear) was generally observed. Dynamic mechanical studies have shown that the dispersion behaves like a semidiluted polymeric solution that roughly follows the Zimm model of viscoelasticity. This behavior accounts for its unique stability and miscibility with water at any proportion without precipitation. On drying or leaving the sample for 7 days, Fe3+ induced partial crosslinking of PVA chains takes place via -OH groups, although complete gelling does not occur. The dispersion forms flexible and uniform films on glass and metal surfaces that does not dissolve after complete drying; this observation combined with shear thinning encourages its application as ink or paint. (C) 2011 Wiley Periodicals, Inc. J Polym Sci Part B: Polym Phys 49: 792-800, 2011