Scanning electron microscopy studies of PEDOT prepared by various electrochemical routes

Polyethylenedioxythiophene (PEDOT) is electrochemically prepared as a film on stainless steel (SS) substrate by galvanostatic, potentiostatic and potentiodynamic methods. The oxidation of EDOT to PEDOT takes place at potentials ≥0.75 V vs. SCE (saturated calomel electrode). The growth of PEDOT is continuous during galvanostatic and potentiostatic modes of preparation. On the other hand, the preparation is discontinuous during multicycle potentiodynamic method. This route leads to layer by layer formation, each layer being formed in a potential cycle. The morphology of PEDOT prepared at low current densities, low potential and low potential range during cycling is essentially globular. The globules develop porosity at higher current density (c.d.) and higher potentials in the case of galvanostatic and potentiostatic routes, respectively. In the case of higher potential range of potentiodynamic deposition, however, the morphology becomes rod-like and fibrous. This is attributed to discontinuous, layer by layer formation of PEDOT and also to its oxidation.