Investigations of electrochemical polymerization processes of thin poly(pyrrole) films and its application to anion sensor based on surface plasmon resonance

Abstract

A study of the response behavior of anion to surface plasmon resonance (SPR) based sensor, in which a Poly(pyrrole) (Ppy) modified thin gold film was used as a sensor chip is described. In situ surface plasmon resonance and electrochemical methods were used to investigate the electropolymerization and doping/dedoping processes of thin Ppy film. The electropolymerization of pyrrole was carried out under cyclic voltammetric conditions, and simultaneously monitored by in situ SPR. It has revealed that the transition between the reduced state and oxidized state of the Ppy, corresponding to the doping/dedoping of anions, can lead to very distinct changes in SPR signal at a fixed angle of incident laser beam. Furthermore, it has demonstrated that the concentration, the charge and size of anions, as well as the film thickness play important roles in the ingress/egress process of anions. Based on this, this combination of experimental approaches can be used to detect Cl−. SPR signal exhibited a good linear relationship with the concentration of Cl−.