Surface and electrochemical study of DBSA‐doped polypyrrole films grown on stainless steel

Abstract

Electrically conducting polypyrrole films doped with dodecylbenzenesulphonic acid (PPy-DBSA) have been electrochemically polymerized on stainless steel. The surface and electrochemical properties of the films were investigated by a combination of cyclic voltammetry (CV), scanning electron microscopy (SEM) and x-ray photoelectron spectroscopy (XPS). The CV results showed an irreversible reaction of electropolymerization. All PPy-DBSA films had a nodular or cauliflower-like surface morphology. The grain size was dependent on the growth current density and the growth time. The ratio of incorporated DBSA anions to pyrrole repeat units in the films was ∼1 : 2. The doping level, calculated from the positive charge accumulated in the polymer chain (at.% ratio .N + + N 2+ //N total /, varied as a function of the growth current density and the growth time. The maximum doping level occurred at a growth current density of 0.5 mA cm −2 , consistent with an oxidation peak of the pyrrole monomer observed by CV. The interfacial layer between the polymer and substrate was also studied. A sulphur-rich layer was observed, indicating the presence of a thin layer of DBSA at the interface. In addition, iron was detected on the metal side of the film as a result of its dissolution from the stainless-steel electrode during the electropolymerization process. These results have implications for the use of polypyrrole films as environmentally friendly corrosion mitigants.

Electrogeneration of Polypyrrole/Alginate Films for Immobilization of Glucose Oxidase

“…It can be seen that pure PPy film typically presents a ''cauliflower'' morphology. [10,11] The average diameter of the particles is about 1-2 mm. In Figure 1B, the conducting film prepared from 0.2 wt.-% pSA and 0.05 M pyrrole aqueous solution of pH ¼ 1.07 also had particles measuring about 1-2 mm, with some much smaller particles on the cauliflower surface, indicating that the main dopant is probably chloride ion.…”

Electropolymerization of DBSA‐doped polypyrrole films on PTFE via an electroless copper interlayer

“…The doping level may be calculated also using the [S total ]/[N total ] ratio and was found to be 42%. From the previous study 39 we found that excess DBSA on the DBSA-doped polypyrrole film was not removed by the rinsing process and was observed by SEM. The former calculation of doping level, therefore, is believed to be more accurate.…”

“…23 These XPS data indicate that the surface composition of a DBSA-doped polypyrrole film deposited on Cu/PTFE is similar to those shown in our previous reports of DBSA-doped polypyrrole films grown on electropolished copper 32 and stainless steel. 39 The doping level-calculated from the ratio of total positively charged nitrogen to total nitrogen [ N 1C C N 2C /N total ]-of the polypyrrole/Cu/PTFE multilayer film was found to be 39%. The doping level may be calculated also using the [S total ]/[N total ] ratio and was found to be 42%.…”

Potentiometric Urea Biosensor Based on a Urease‐Immobilized Polypyrrole

“…A two-electrode electrochemical cell was set up and the constant potential of 1.5 V was applied for 10 min at room temperature (28 C). According to the previous study, [11] the PPy film with the maximum doping level was achieved when the potential of 1.5 V was applied in the electropolymerization process. Black PPy film coated electrode was washed thoroughly with water to eliminate any loosely bound species.…”