PREPARATION AND CHARACTERIZATION OF POLYANILINE COLLOIDS USING A MONODISPERSE POLY(ETHYLENE OXIDE)-BASED STERIC STABILIZER

The synthesis of polyaniline colloids using a new polymeric steric stabiliser of narrow molecular weight distribution based on poly(ethylene oxide) is reported. This model stabiliser contains one tertiary amine group per polymer chain which is believed to participate in the in situ aniline polymerisation, leading to the chemical grafting of the stabiliser onto the surface of the polyaniline particles. These polyaniline colloids were characterised by a wide range of techniques including electron microscopy, FTIR and visible absorption spectroscopy, microanalysis, d.c. conductivity and thermogravimetric analysis. The colloids possess a polydisperse non-spherical morphology and remarkably high solid-state electrical conductivity (0.1-1.0 S cm-1), despite the presence of the electrically insulating grafted stabiliser. The mass ratio of grafted stabiliser: polyaniline was determined indirectly by H-1 NMR spectroscopy analysis of the post-reaction supernatant solutions. In addition, flocculation experiments were carried out to assess the aggregation stability of these dispersions in the presence of added electrolyte.