title: Redox switching of polyoxometalate-methylene blue-based layer-by-layer films.
abstract: Iron-substituted crown-type polyoxometalate (POM) [P(8)W(48)O(184)Fe(16)(OH)(28)(H(2)O)(4)](20-) has been successfully immobilized onto glassy carbon electrode surfaces by means of the layer-by-layer (LBL) technique employing the cationic redox active dye, methylene blue (MB). The constructed multilayers exhibit pH-dependent redox activity for both the anionic POM and the cationic dye moieties, which is in good agreement with their solution behavior. The films have been characterized by alternating current impedance, atomic force microscopy, and X-ray photoelectron spectroscopy, whereby the nature of the outer layer within the assemblies was found to have an effect upon the film's behavior. Preliminary investigations show that the POM dye-based films show electrocatalytic ability toward the reduction of hydrogen peroxide, however, only when there is an outer anionic POM layer.
authors.affiliation: Electrochemistry Research Group, Department of Applied Science, Dundalk Institute of Technology, Dublin Road, Dundalk, County Louth, Ireland.
authors.forename: Nargis
authors.initials: N
authors.lastname: Anwar
authors.forename: Mikhail
authors.initials: M
authors.lastname: Vagin
authors.forename: Rashda
authors.initials: R
authors.lastname: Naseer
authors.forename: Shahzad
authors.initials: S
authors.lastname: Imar
authors.forename: Masooma
authors.initials: M
authors.lastname: Ibrahim
authors.forename: Sib Sankar
authors.initials: SS
authors.lastname: Mal
authors.forename: Ulrich
authors.initials: U
authors.lastname: Kortz
authors.forename: Fathima
authors.initials: F
authors.lastname: Laffir
authors.forename: Timothy
authors.initials: T
authors.lastname: McCormac