bipy bipy

Figure 4. Styryl terthiophene monomers synthesized.

to solubilize the aniline monomer and to ensure that the conducting emeraldine salt PAn • HA form of the polymer is produced [see structure (III)]. The most common chemical oxidants are ammonium persulfate or ferric chloride, in which cases HSO-/SO4- or Cl- anions are incorporated as the dopant anions A- at the radical cation nitrogen sites along the PAn chains.

Using electrochemical polymerization, a much wider range of dopant anions may be incorporated along the polyaniline chains, depending on the electrolyte employed. After deposition on the working electrode, films of the PAn • HA may often be removed as mechanically robust, standalone membranes. On the other hand, chemical polymerization has the advantage of being a simple process capable of producing bulk quantities of PAn • HA powders on a batch basis.

In both chemical and electrochemical polymerization the initial and rate-determining step is believed [49-51] to

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