In situ spectroelectrochemistry, electrosynthesis and growth rates of conducting polypyrrole and poly N-methylpyrrole on gold and indium tin oxide glass modified by thiolated α-cyclodextrin self-assembled monolayer’s (SAMs)

Abstract

Electrochemical synthesis, in situ spectroelectrochemistry and growth rates of conducting polypyrrole (PPy) and poly(N-methylpyrrole) (PNMPy) on bare and modified gold and indium tin oxide (ITO) glass with thiolated α-cyclodextrin (T-α-CD) self-assembled monolayers (SAMs) have been investigated. The films modifiers of functionalized SAMs were characterized by means of CV, in situ UV–visible spectroscopy, in situ conductivity measurement and scanning electron microscopy (SEM). The polymerization reactions are 0.73 and 0.81 orders with respect to the pyrrole and N-methylpyrrole concentrations and 0.61 and 0.64 orders with respect to the amount of PPy and PNMPy. The kinetic results indicate that the polymerization growth rate of PPy is faster than PNMPy. However, the polymerization growth rates of both polymers at the modified electrodes SAMs are slower than that at bare gold electrode. The in situ conductivity of the polymers on bare and modified gold electrodes have been studied. The results indicates that the in situ conductivity of polymers on modified gold electrode were lower by around 1–2 orders of magnitude than those of polymers on bare gold electrodes. The in situ UV–visible spectroscopy of polymers on modified ITO/glass with T-α-CD-SAMs indicates a characteristic absorption’s bands. Scanning electron microscopic photos reveal that the T-α-CD may act as molecular templates for electrochemical polymerization of conducting PPy and PNMPy.