COMPETITION BETWEEN DOPANTS ON REDOX REACTION OF POLYPYRROLE

The surface of PPy prepared in a multiple electrolyte solution such as NaDS-NaClO4 in H2O shows a coarser structure than that of the polymer prepared in a single electrolyte system. DS- with a large aliphatic chain is used as a dopant in preparation of PPy. The dopant is trapped in PPy when the polymer is reduced in an aqueous system. A cation Na+ or K+ is inserted into the polymer to balance the free DS- liberated form and remained in it on reduction. PPy doped with DS- shows a high degree of redox reactivity in the system of TBADS-AN but a poor stability in repeated redox process. The degree and rate of redox reactivity enhance when an aqueous solution of NaClO4 is used as an electrolyte system. Both Na+ and ClO4- take part in the redox reaction and the reduction process is intense at only one current potential.