This case may be happened because of :

1- Oxidation of all amounts of monomer during the first cycle.

2- This probably due to electronic interference of some groups in monomer structure.

3- Formation of a protective layer on the electrode which lead to inhibit of electropolymerization process.

Dear Mohammed qasim Mohammed thanks for your answer,

Did you have any idea about how I can check these phenomenas.

Thanks lot, Said ABBOUT.

Dear

you can try to increase the concentration of monomer. for second and third point you can see this article "New conducting carrier materials: polyalkylthiophene

functionalized with amino group and its protected forms"

regards

Dear Mohammed qasim Mohammed

Thank you.

Did you have any idea about the range of electropolymerization potential