Electrosynthesis of polypyrrole (PPy) was studied in aqueous lithium iodide solution. The electrochemical polymerization showed features of two-dimensional growth and the reaction was catalyzed by the I-2/I- couple. The potentiometric response of PPy doped with iodide (PPy(I)) was studied both in iodide solutions and solutions containing the redox couple I-2/I- with a fixed concentration ratio 0.4 but varying the initial concentration of iodide in the range 10(-5)-1.0 M. Linear, anionic response was observed in the concentration range 10(-1)-10(-3) M when only iodide species was present. However, contribution of the redox response to the overall potentiometric response increased with increasing concentration of I-2 although the concentration ration between iodine/iodide was kept constant. The influence of phosphate buffer on the electroactivity of PPy doped with iodide was also studied.
- phosphate buffer
- two-dimensional growth