Study on thiolation of polyaniline with 2-mercaptoethanol in HCl and KCl at constant potential

Thiolation of polyaniline (PANI)

films with 2-mercaptoethanol was studied by cyclic voltammetry (CV)

and chronoamperometry (CA). The sulfur content in the PANI

films thiolated in acidic and neutral

conditions at different applied potentials was used as the measure of the degree of thiolation. FTIR

spectroscopy was used to study the changes in the PANI structure after thiolation. The thiolation

experiments were performed in 1.0 M HCl and 0.1 M KCl with three different thiol concentrations.

Thiolation provides an easy and straight-forward method to bind covalently molecules, even

biomolecules to the PANI backbone. Optimization of the thiolation conditions is the key issue when

designing PANI-based biosensors. The results show that with the CA technique it is possible to bind

thiolated molecules on PANI both in HCl and in KCl. Furthermore, the results indicate that the potential

applied, the thiolation medium and the concentration of the added thiol affect the thiolation process. CA

offers an opportunity to enhance the thiolation allowing to some extent also to control the entire process

opening up new possibilities to prepare PANI based biosensor substrates.