Investigation of Styrene−Methacrylic Acid Block Copolymer Micelle Doped Polypyrrole Films by Scanning Electrochemical Microscopy

Abstract

The preparation of a novel type of polypyrrole films is described. Spherical styrene−methacrylic acid block copolymer micelles with a hydrophobic core of 18 nm and a hydrophilic corona of 100 nm were incorporated in polypyrrole films by electropolymerization from a mixed solvent with 80 vol % of dioxane and 20 vol % of water. The properties of the block copolymer micelle doped polypyrrole films were investigated by cyclic voltammetry and scanning electrochemical microscopy (SECM). It was found that the self-assembled block copolymer micelles in polypyrrole behave as polyanions and the charge compensation by cations has been identified during electrochemical switching of the polymer films. The ejection of cations from the films was monitored by SECM using an amperometric or potentiometric ultramicroelectrode tip during different potential programs (potential step and cyclic voltammetric scans) applied on the block copolymer micelle doped polypyrrole modified substrate electrodes. The incorporation of self-assembled block copolymer micelles into the polypyrrole structure can represent an interesting way to change its properties. Different kinds of hydrophobic molecules can be dissolved in the core of the micelle and thus incorporated into the polypyrrole films.