Hemoglobin-biocatalysts synthesis of a conducting molecular complex of polyaniline and sulfonated polystyrene

A new biocatalyst route for the synthesis of a conducting polyaniline (PANI)/sulfonated polystyrene (SPS) complex is presented. Hemoglobin (Hb) is used to polymerize aniline in the presence of a polyanionic template SPS. The synthesis is simple, and the conditions are mild in that the polymerization may be carried out in lower pH (1.0-4.0) buffered aqueous solution, with a stoichiometric amount of hydrogen peroxide and a catalytic amount of Hb. UV-Vis absorption, Fr-IR, elemental analysis, and conductivity measurements, cyclic voltammetry (CV), thermogravimetric analysis (TGA), fluorescence spectra and XRD studies all confirm that the electroactive form of PANI, similar to that which is traditionally chemically synthesized, is formed and complexed to the SPS. Cyclic voltammetry studies show three sets of redox peaks over the potential range of -0.2 to 1.0 V, and the formation of peak does not change at a series of scanning 20 times, which suggests that the PANI/SPS complex is more stable. The PANI complexes produced at different pH show the different conductivity. This biomimetic approach offers unsurpassed case of synthesis, processability, stability, and environmental compatibility. (c) 2005 Elsevier B.V. All rights reserved.