Surface Characterization of Polypyrrole-Coated Polystyrene Latex by X-ray Photoelectron Spectroscopy

The surface composition of electrically conductive polypyrrole-coated polystyrene latex particles has been examined by X-ray photoelectron spectroscopy (XPS). We have systematically characterized the surface of polystyrene (PS), poly( N -vinylpyrrolidone) (PNVP), chloride-doped polypyrrole (PPyCl) powder, and PNVP-stabilized PS latex in order to determine the relative contributions of PS (core), PNVP (stabilizer), and PPyCl (shell) to the surface composition of the PPyCl-coated PS latex. XPS was found to be very effective in detecting PNVP at the surface of uncoated PS latex using N1s signal as an elemental marker and showed that the former polymer contributes to ca . 50% of the PS latex surface. In contrast, the surface composition of PPyCl-coated PS latex was found to be very PPyCl-rich, since the PPyCl bulk powder and the PPyCl-coated PS latex have very comparable XPS spectra. However, some additional iron chloride species (FeCl 2 and/or FeCl 3 - ) were also detected as impurities at the surface of the coated latex.