abstract
In this work, polyelectrolyte coatings assembled on glassy carbon/thin mercury film electrodes, as an adsorbed layer of poly(sodium 4-styrenesulfonate) (PSS), were studied. The goal was to search for the best conditions for the production of stable PSS-coated electrodes that could present high negative charge densities within the thin polymeric film, providing a fast and significant electrostatic cation accumulation. Square-wave anodic stripping voltammetry was applied to measure the amount of incorporated lead used as the reference cation. The influence of the composition of the PSS solution, the amount of deposited PSS, molecular weight and of the ionic strength of the electrolyte solution, on the features of the PSS coatings for ion-exchange voltammetry was studied. The PSS films morphology was assessed by SEM. The best PSS coating performance was found for the electrodes prepared from water solutions with a molecular weight of at least 70,000, and a mass loading of ca. 8 mu g mm(-2). In these conditions a three fold increase was observed in low ionic strength (0.0032 M) media. However, this improvement was not sufficient for the application of direct ion-exchange voltammetry, thus different strategies to obtain polymer films with higher charge densities have to be envisaged. (c) 2008 Elsevier B.V. All rights reserved.
keywords
SODIUM POLY(STYRENE SULFONATE); GLASSY-CARBON ELECTRODES; ION-EXCHANGE VOLTAMMETRY; STRIPPING VOLTAMMETRY; POLYELECTROLYTE MULTILAYERS; CHAIN CONFORMATION; TRACE-METALS; PERFORMANCE; DEPOSITION; CHLORIDE
subject category
Chemistry; Electrochemistry
authors
Silva, CP; Carapuca, HM; Rocha, LS; Pinheiro, JP
Groups
acknowledgements
The authors thank to Fundacao para a Ciencia e a Tecnologia (FCT) for financial support (project POCI 2010-Feder- POCI/AMB/ 55939/2004). Luciana Rocha acknowledges FCT for her PhD Grant. Thanks are also due to CICECO.