Poly(Neutral Red) in Multilayer Electrode Systems

Abstract

The present work describes the properties of neutral red polymer after electrochemical modification using a multilayer concept. The aim of this modification was to enhance the potentiometric properties of poly(neutral red) (PNR) electrodes by improving their binding characteristics. The electrochemical modification involved the use of a multilayer settlement of film coating both to affect selectivity and to suppress the platinum support influence, which can also have an effect on the electrode signal. The first layer was polythiophene, which shielded the platinum and strengthened the polymerization of the next layer. The second layer consisted of polypyrrole, able to react non-specifically with almost all anions. Selectivity was introduced to the layered system by the final layer of PNR controlling the selectivity of the potentiometric response, which is also affected by other layers. It was observed that the variation of the layer order (in the systems of polythiophene, polypyrrole and PNR) and thickness can be used to control the selectivity, and selectivity order, of electrodes to anions of carboxylic acids. The shielding of platinum influence to electrode response by the introduction of an additional polymeric layer was proved.