A Combined Electrochemical Quartz-Crystal Microbalance Probe Beam Deflection (EQCM-PBD) Study of Solvent and Ion Transfers at a Poly[Ni(saltMe)]-Modified Electrode During Redox Switching

Vilas-Boas, Miguel; Henderson, Mark J.; Freire, Cristina; Hillman, A. Robert; Vieil, E.

doi:10.1002/(sici)1521-3765(20000403)6:7<1160::aid-chem1160>3.0.co;2-2

Cited by 17 publications

(36 citation statements)

References 42 publications

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“…Cyclic voltammograms in 0.1 mol dm −3 TEAP/CH 3 CN of [Cu(salen)] and [Cu(saltMe)] monomers are very similar and resemble those observed for solutions of nickel complexes with the same ligands [1,3]. They are typical of irre-Fig.…”

Section: Electrochemical Polymerisation and Redox Switching 211 Polymerisationsupporting

confidence: 58%

“…These results indicate a change from a thin-layer regime to a semiinfinite diffusion control. This transition between the two regimes has been observed for nickel and other polymermodified electrodes [2,3,5,17,18] and as suggested by Bartlett [19], is determined by the interplay between scan rate and kinetics of charge transport throughout the film. Plots of E p versus log ν for thick polymers (Fig.…”

Section: Cyclic Voltammetric Studies Of Film Dynamicsmentioning

confidence: 52%

“…The films are moderately stable; cycling on a time scale of 12 h results in almost complete loss of electroactivity, but with poly[Cu(saltMe)] being significantly more stable than poly[Cu(salen)]. Copper polymers are less stable than the analogous nickel polymers, notably poly[Ni(saltMe)], which exhibits a remarkably high electrochemical stability [2,3]. Loss of electroactivity is not accompanied by visual loss of material deposited at the electrode surface.…”

Section: Redox Switchingmentioning

confidence: 99%

“…By using the approach proposed in previous studies on poly[Ni(salen)]-based polymers [1][2][3], we can consider, as a first approximation, that three processes may contribute to the overall charge passed during a polymerisation scan: polymerisation and the two limiting situations for oxidation, a ligand-based redox process, and a metal-based redox process. The number of electrons per monomer unit associated with each process is: 2 electrons (and 2 protons) for polymerisation, z electrons for copper-based redox switching (with the constraint that z = 0 or 1) and 2y electrons for the ligandbased redox switching (y electrons per phenyl ring).…”

Section: Coulometrymentioning

confidence: 99%

“…Preparation and characterisation of metal salen-based electroactive polymers is an active field of research due to their potential application as electrocatalysts, chemical sensors or optical devices. We have electrosynthesised several nickel salen-based polymers and we have used cyclic voltammetry and chronoamperometry to study film redox activity and charge transport [1][2][3], UV-vis, FT-IR and EPR spec-troscopies to explore aspects of polymer electronic structure [1,4], and the electrochemical quartz crystal microbalance (EQCM) and probe beam deflection (PBD) to characterise ion and solvent transfer processes driven by redox switching [3,5], One important aspect that has emerged from the results is that the nickel centre is not involved in polymer oxidation: the polymer is best described as a polyphenylene-type compound (a "conducting polymer"), rather than an aggregation of discrete electroactive nickel complexes. The role of the nickel centre is to define the nature of the bridge between the biphenylene moieties in the ligand.…”

Section: Introductionmentioning

confidence: 99%

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Spectroelectrochemical characterisation of copper salen-based polymer-modified electrodes

Martins

Vilas‐Boas

Castro

et al. 2005

Electrochimica Acta

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Electrogenerated polymers based on copper salen-type complexes were characterised electrochemically and by in situ UV-vis and ex situ EPR spectroscopy. The films, poly[Cu(salen)] and poly[Cu(saltMe)], exhibit reversible oxidative electrochemical behaviour in a wide potential range (0.0-1.5 V). Different regimes for charge transport behaviour are accessed by manipulation of film thickness and experimental time scale: thin films (surface concentration, Γ < ca. 80 nmol cm −2 ) show thin-layer/surface behaviour in the scan rate range used (0.020-2.0 V s −1 ), whereas thicker polymers (Γ > ca. 90 nmol cm −2 ) exhibit a changeover from thin-layer to diffusion control regime at a critical scan rate that depends on polymer and film thickness: 0.15-0.20 V s −1 for poly[Cu(salen)], 90 < Γ < 130 nmol cm −2 and 0.20-0.30 V s −1 for poly[Cu(saltMe)], 170 < Γ < 230 nmol cm −2 .UV-vis and EPR spectroscopies have allowed the characterisation of electronic states in the reduced and oxidised forms. The role of the copper atom during film oxidation was probed by combining UV-vis data with EPR on copolymers of the copper and nickel complexes. Data from both techniques are consistent and indicate that polymerisation and redox switching are associated with ligand-based processes. EPR of Ni-doped Cu polymers provided evidence for the non-involvement of the metal centre in polymer oxidation; like the analogous nickel polymers, copper polymers behave like delocalised -system ('conducting') rather than discrete site ('redox') polymers.

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Section: Electrochemical Polymerisation and Redox Switching 211 Polymerisationsupporting

confidence: 58%

Section: Cyclic Voltammetric Studies Of Film Dynamicsmentioning

confidence: 52%

Section: Redox Switchingmentioning

confidence: 99%

Section: Coulometrymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Spectroelectrochemical characterisation of copper salen-based polymer-modified electrodes

Martins

Vilas‐Boas

Castro

et al. 2005

Electrochimica Acta

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The Electrochemical Quartz Crystal Microbalance

Hillman

2003

Encyclopedia of Electrochemistry

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This chapter reviews the development and use of the electrochemical quartz crystal microbalance (EQCM) as an in situ probe of interfacial processes involving the formation, properties, and redox switching of multilayer films. For films that are sufficiently rigid and/or thin (termed acoustically thin ), the EQCM functions as a quantitative gravimetric probe of surface population changes. This well‐established methodology is now being used to explore both thermodynamic and kinetic aspects of film compositional changes, for example, in response to electrochemical stimuli. Correlation of mobile species (ion and solvent) population changes—within the effectively static film matrix—with electrochemical control and response functions (potential, current, and charge) now provides mechanistic information. Combination with other in situ (e.g. optical or spectroscopic) techniques is a developing area and can facilitate separation of individual ion and solvent transfers. For films that are softer and/or thicker (termed acoustically thick ), the acoustic wave is attenuated during passage across the film, which in turn undergoes acoustic deformation. The EQCM now responds primarily to film viscoelastic properties, that is, film (rather than mobile species) dynamics. This is a developing area, but it is now possible to extract film shear modulus components (storage and loss moduli); these are found to respond significantly to the film redox state (controlled via potential or charge), temperature, timescale (frequency), and environment (both solvent and electrolyte ions). These effects are reviewed with selected examples from a diverse range of materials, encompassing metals, metal oxides, semiconductors, metal coordination complexes, and redox, conducting, and insulating polymers.

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Electrochemical behaviors of poly(ferrocenylsilane) solutions

Wang

et al. 2006

J of Applied Polymer Sci

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The electrochemical behaviors of two kinds of poly(ferrocenylsilanes) (PFS) with different substituent groups in CH 2 Cl 2 solutions were investigated by means of cyclic voltammetry (CV) and electrochemical quartz crystal microbalance. The results demonstrated that the CV processes of the PFS on the glass carbon electrode surface in CH 2 Cl 2 solutions are the diffusion-controlled reversible processes. The oxidative state of PFS forms an adsorption layer on the electrode surface during the oxidation process. The interaction of active ferrocene centers along the main chain induces the stepwise redox process, and makes the CV waves of the PFS solutions present two couples of peaks. The diffusion coefficients of PFS in CH 2 Cl 2 solution are much larger than those of PFS in films. The different electrochemical behaviors of the two PFS solutions indicated that the molecular structure of polymer has influence on the electrochemical properties of the PFS.

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A Combined Electrochemical Quartz-Crystal Microbalance Probe Beam Deflection (EQCM-PBD) Study of Solvent and Ion Transfers at a Poly[Ni(saltMe)]-Modified Electrode During Redox Switching

Cited by 17 publications

References 42 publications

Spectroelectrochemical characterisation of copper salen-based polymer-modified electrodes

Spectroelectrochemical characterisation of copper salen-based polymer-modified electrodes

The Electrochemical Quartz Crystal Microbalance

Electrochemical behaviors of poly(ferrocenylsilane) solutions

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