Metal chelation and spatial profiling of components in crown ether functionalised conducting copolymer films

Glidle, Andrew; Hillman, A. Robert; Ryder, Karl S.; Smith, Emma L.; Cooper, Jonathan M.; Dalgliesh, Robert M.; Cubitt, R.; Geue, Thomas

doi:10.1016/j.electacta.2009.04.027

Cited by 10 publications

(15 citation statements)

References 35 publications

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“…composition (spatial profiles of polymer and solvent) in situ under electrochemical control. We have demonstrated the capability of neutron reflectivity (NR) measurements to provide such information for a range of electroactive films [42][43][44][45][46][47], including changes in mobile species (ion and solvent) distributions with film charge state [45,46] and electrolyte concentration [46], and polymer/polymer interpenetration to distinguish composites from bilayers [43]. The penetrating power of neutrons, enabling them to reach the "buried" interfaces associated with the polymer film, makes NR the ideal technique.…”

Section: Accomplishment Of These Objectives Requires a Technique Capamentioning

confidence: 99%

“…Deposition solutions were prepared containing deuterated pyrrole in 0.1 M NaClO 4 / H 2 O. The working electrodes were gold coated quartz blocks, prepared as described previously [46,47]. Briefly, quartz substrates (10 cm x 5 cm x 1 cm) were cleaned by sonication in soap solution, rinsed with deionised water, sonicated in deionised water and dried with compressed air.…”

Section: Materials and Reagentsmentioning

confidence: 99%

“…Electrochemical measurements were performed using a Biologic SP-200 potentiostat and processed using the EC-Lab software. All films were deposited and measured in previously described NR/EC cells [43][44][45][46][47]. When assembled, the exposed areas of the working electrodes were in the range ca.…”

Section: Instrumentationmentioning

confidence: 99%

“…These values are "bookends" when the film is inserted bulk media. Single and multi-layer models were used to represent solvation gradients in the film [44][45][46][47].…”

Section: Data Interpretationmentioning

confidence: 99%

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Effect of electrochemical control function on the internal structure and composition of electrodeposited polypyrrole films: A neutron reflectometry study

Beebee

Watkins

Sapstead

et al. 2019

Electrochimica Acta

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Electrodeposited conducting polymer films derived from aromatic monomers are known to possess properties that depend significantly on the deposition protocol, particularly the electrochemical control function employed. This study explores the underlying reasons for this common observation for the specific case of polypyrrole films deposited from aqueous media onto gold electrodes under potentiostatic, potentiodynamic and galvanostatic control. Although the control functions impose different conditions, the control parameters (potential, potential range and scan rate, and current) were selected so as generate films at comparable rates; this avoids inappropriate attribution of structural and compositional variations to different thickness regimes, irrespective of how they were generated. In each case, film deposition was periodically interrupted and the film characterised by specular neutron reflectivity measurements. By using d 4pyrrole monomer in H 2 O solvent, the isotopic selectivity of neutron reflectivity was used to extract polymer and solvent concentration profiles as a function of distance from the electrode/film interface. Spatial integration of these profiles was used to quantify total film solvent populations; these are expressed as solvent volume fractions. Films grown under the three different control regimes have measurably distinct solvent volume fraction profiles and there is evolution of these profiles with increasing thickness. Ultimately, for the conditions employed, the order of increasing porosity (i.e. solvent content) by control function was potentiostatic < potentiodynamic < galvanostatic. At the end of the deposition process, the films were transferred to monomer-free electrolyte and redox cycled. This resulted in an overall increase in film solvation, but little difference in solvation with redox state (doping level). We conclude that film structure and associated solvation level do retain some memory of deposition protocol, but also respond to the medium of exposure.

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Section: Accomplishment Of These Objectives Requires a Technique Capamentioning

confidence: 99%

Section: Materials and Reagentsmentioning

confidence: 99%

Section: Instrumentationmentioning

confidence: 99%

“…These values are "bookends" when the film is inserted bulk media. Single and multi-layer models were used to represent solvation gradients in the film [44][45][46][47].…”

Section: Data Interpretationmentioning

confidence: 99%

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Effect of electrochemical control function on the internal structure and composition of electrodeposited polypyrrole films: A neutron reflectometry study

Beebee

Watkins

Sapstead

et al. 2019

Electrochimica Acta

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“…Looking ahead to the NR part of the study, solvation might be expected to increase these values by 50-100%, since typical solvent volume fractions for electroactive polymer lms are in the range 0.3 < f S < 0.5. [51][52][53][54] This overall scenario is appropriate both for a NR experiment (to explore structure) and lling of the interridge "trenches" in a typical ngerprint deposit (to accomplish practical visualization). As a nal observation, the different thicknesses of these two PPyFMOC and PPyNH 2 lms containing essentially the same number of monomer units (irrespective of whether one compares two dry lms or two solvated lms) shows the potential for generation of free volume by FMOC elution from a lm.…”

Section: Optimization Of Lm Depositionmentioning

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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