Effect of electrolyte concentration and nature on the morphology and the electrical properties of electropolymerized polypyrrole nanotubules

Polypyrrole (PPy) with four different counterions was electrochemically synthesized in homemade polycarbonate particle track-etched membranes with different pore sizes. A dependence of the PPy growing rate on the pore size and on the electrolyte nature and concentration has been observed. The morphology of the different template-synthesized nanostructures has been carefully analyzed by field-emission scanning electron microscopy. In all cases, nanotubules were observed. However, their thickness depends on the pore diameter of the template membrane and on the nature of the supporting electrolyte. The electrical conductivity of PPy in such a structure is known to increase compared to the bulk conductivity, which is also shown here. In addition Raman spectroscopy showed that the relative conjugation length increases with decreasing pore size.