Redox Controlled Partition and Spatial Distribution of Solvent and Salt in Electroactive Polyvinylferrocene Films

Glidle, Andrew; Cooper, Jonathan M.; Hillman, A. Robert; Bailey, Lee; Jackson, and Angela; Webster, John R. P.

doi:10.1021/la027053+

Cited by 29 publications

(59 citation statements)

References 22 publications

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“…Such competitive anion ingress and cation egress processes for charge compensation are well known for both conductive polymer and redox polymer thin films. [54][55][56][57] Taken together, it is reasonable to assume that the first and third terms of Equation 2 are comparable for SAM2 and SAM2b. Therefore, by comparing the SPR angle changes for each, we have a means to quantify the contribution film reorganization alone, and to estimate the SAM thickness change (Δd) upon oxidation of the Fc label.…”

Section: Discussionmentioning

confidence: 99%

Influence of Molecular Dipole Moment on the Redox-Induced Reorganization of α-Helical Peptide Self-Assembled Monolayers: An Electrochemical SPR Investigation

Wain

Mandal

et al. 2008

J. Phys. Chem. C

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Self-assembled monolayers (SAMs) of ferrocene-labeled α-helical peptides were prepared on gold surfaces and studied using electrochemical surface plasmon resonance (EC-SPR). The leucine-rich peptides were synthesized with a cysteine sulfhydryl group either at the C-or N-terminus, enabling their immobilization onto gold surfaces with control of the direction of the molecular dipole moment. Two electroactive SAMs were studied, one in which all of the peptide dipole moments are oriented in the same direction (SAM1), and the other in which the peptide dipole moment of one peptide is aligned in the opposite direction to that of its surrounding peptide molecules (SAM2). Cyclic voltammetry combined with SPR measurements revealed that SAM reorientations concomitant with the oxidation of the ferrocene label were more significant in SAM2 than in SAM1. The substantially greater change in the peptide film thickness in the case of SAM2 is attributed to the electrostatic repulsion between the electrogenerated ferrocinium moiety and the positively charged gold surface. The greater permeability of SAM1 to electrolyte anions, on the other hand, appears to effectively neutralize this electrostatic repulsion. The film thickness change in SAM2 was estimated to be 0.25 ± 0.05 nm using numerical simulation. The timescale of the redox-induced SPR changes was established by chronoamperometry and time-resolved SPR measurements, followed by fitting of the SPR response to a stretched exponential function. The time constants measured for the anodic process were 16 and 6 ms for SAM1 and SAM2 respectively, indicating that the SAM thickness changes are notably fast.

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Section: Discussionmentioning

confidence: 99%

Influence of Molecular Dipole Moment on the Redox-Induced Reorganization of α-Helical Peptide Self-Assembled Monolayers: An Electrochemical SPR Investigation

Wain

Mandal

et al. 2008

J. Phys. Chem. C

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“…[18][19][20] Studies into the electrochemical behaviour of pVFc films have shown how the voltammetric response is dependant on the anion present within the solution. 8,10,[21][22][23][24][25][26][27][28] The stability of the oxidation wave upon repetitive scanning was found to be dependant on the size of the anion, with larger anions producing less stable signals. This anion sensitivity was minimized by controlling both the scan rate and potential range.…”

Section: Introductionmentioning

confidence: 99%

Vinylferrocene Homopolymer and Copolymers: An Electrochemical Comparison

Robinson

Lawrence

2008

ANAL. SCI.

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Poly(vinylferrocene) (pVFc) homopolymer was synthesized by free radical polymerization, along with a series of pVFcbased copolymers containing either styrene, vinylanthracene or methylmethacrylate. This report details the electrochemical experiments conducted to examine the stability of the various pVFc based polymers, which is shown to be critically dependent on the extent of copolymerization. A trend was found that when the concentration of co-monomer was decreased, electrochemical stability was enhanced. Furthermore incorporation of a second monomer into the polymer chain produced a profound effect on the scan rate behaviour of the vinylferrocene moiety. As the concentration of co-monomer was decreased, the behaviour tended towards that of a diffusion controlled process. These results are of vital significance for the development of pVFc-based electrochemical sensors.

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“…The principles of neutron reectivity data analysis 47 and the issues arising for samples involving "wet" interfaces under electrochemical control 48 have been described elsewhere. The variation with momentum transfer of reectivity from an interface, R(Q), is determined by the depth prole of the scattering length density, Nb, where N represents the concentration of scattering atoms present and b is their scattering length; the value of b is isotopically unique and medium independent.…”

Section: Discussionmentioning

confidence: 99%

Nanoscale control of interfacial processes for latent fingerprint enhancement

et al. 2013

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Latent fingerprints on metal surfaces may be visualized by exploiting the insulating characteristics of the fingerprint deposit as a "mask" to direct electrodeposition of an electroactive polymer to the bare metal between the fingerprint ridges. This approach is complementary to most latent fingerprint enhancement methods, which involve physical or chemical interaction with the fingerprint residue. It has the advantages of sensitivity (a nanoscale residue can block electron transfer) and, using a suitable polymer, optimization of visual contrast. This study extends the concept in two significant respects. First, it explores the feasibility of combining observation based on optical absorption with observation based on fluorescence. Second, it extends the methodology to materials (here, polypyrrole) that may undergo postdeposition substitution chemistry, here binding of a fluorophore whose size and geometry preclude direct polymerization of the functionalised monomer. The scenario involves a lateral spatial image (the whole fingerprint, first level detail) at the centimetre scale, with identification features (minutiae, second level detail) at the 100-200 mm scale and finer features (third level detail) at the 10-50 mm scale.However, the strategy used requires vertical spatial control of the (electro)chemistry at the 10-100 nm scale. We show that this can be accomplished by polymerization of pyrrole functionalised with a good leaving group, ester-bound FMOC, which can be hydrolysed and eluted from the deposited polymer to generate solvent "voids".Overall the "void" volume and the resulting effect on polymer dynamics facilitate entry and amide bonding of Dylight 649 NHS ester, a large fluorophore. FTIR spectra demonstrate the spatially integrated compositional changes. Both the hydrolysis and fluorophore functionalization were followed using neutron reflectivity to determine vertical spatial composition variations, which control image development in the lateral direction.

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Redox Controlled Partition and Spatial Distribution of Solvent and Salt in Electroactive Polyvinylferrocene Films

Cited by 29 publications

References 22 publications

Influence of Molecular Dipole Moment on the Redox-Induced Reorganization of α-Helical Peptide Self-Assembled Monolayers: An Electrochemical SPR Investigation

Influence of Molecular Dipole Moment on the Redox-Induced Reorganization of α-Helical Peptide Self-Assembled Monolayers: An Electrochemical SPR Investigation

Vinylferrocene Homopolymer and Copolymers: An Electrochemical Comparison

Nanoscale control of interfacial processes for latent fingerprint enhancement

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