NONAQUEOUS POLYPYRROLE COLLOIDS - SYNTHESIS AND CHARACTERIZATION

The preparation of sterically-stabilized polypyrrole colloids via a dispersion polymerization route in non-aqueous media is described for the first time. Pyrrole polymerization was achieved using FeCl3 as an oxidant/dopant in organic solvents such as methyl acetate, methyl formate and propyl formate. Macroscopic precipitation was prevented by the use of poly(vinyl acetate) as a polymeric surfactant. Various other surfactants were ineffective and consequently resulted in precipitation of polypyrrole. Several techniques were used for characterization of the dispersions including transmission and scanning electron microscopies (TEM and SEM), thermogravimetric analysis (TGA), charge velocity analysis and visible absorption spectroscopy. TEM indicated a polydisperse spherical morphology with a particle diameter in the range 100-300 nm. The compressed pellet conductivities of the dried dispersion were as high as 0.1 S/cm. These dispersions are often compared with bulk and colloidal polypyrrole prepared in aqueous media. © 1990.