Phospholipid vesicles as soft templates for electropolymerization of nanostructured polypyrrole membranes with long range order

Northcutt, Robert; Sundaresan, Vishnu-Baba

doi:10.1039/c4ta02352h

Cited by 19 publications

(27 citation statements)

References 28 publications

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“…The percentage of redox sites which can be occupied is given by a non-dimensional metric referred to as the 'filling efficiency' (φ ). It is the ratio between the peak charge (q + C ) inserted into the polymer during cyclic voltammetry (CV) to the maximum charge that can be accommodated (q C,max ) based on the total number of redox sites [10]. Mathematically, the relationship is given as:…”

Section: Sense Length Of Ultra-microelectrodesmentioning

confidence: 99%

Nanoscale polypyrrole sensors for near-field electrochemical measurements

Venugopal

Venkatesh

Northcutt

et al. 2017

Sensors and Actuators B: Chemical

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Scanning electrochemical microscopy (SECM) is an electrochemical technique that is used to measure redox activity local to the surface of a sample. The incorporation of shear force (SF) feedback into SECM enables the concurrent acquisition of topographical data. Contemporary SECM measurements require a redox mediator (such as ferrocene methanol (FcMeOH)) for electrochemical measurements; however, redox mediators are detrimental to chemically sensitive materials such as biological cells. In this article, nanoscale polypyrrole membranes doped with dodecylbenzene sulfonate (PPy(DBS)) are deposited at the tip of highly sensitive ultra-microelectrodes (UME) to demonstrate a novel modification of the contemporary SECM-SF imaging technique that operates in the absence of a redox mediator. This technique leverages the redox activity of a PPy(DBS) membrane to locally detect changes in cation concentration. In conjunction with SF imaging, the PPy(DBS) membrane can (i) detect changes in distance from the surface by measuring changes in ion concentration of the diffusion shell, or (ii) detect local cation flux due to cell function when kept at a constant distance from the cell surface through SF-imaging techniques. Therefore, we predict this technique to enable high resolution mapping of surface cation concentrations and impact the field of biological imaging.

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Section: Sense Length Of Ultra-microelectrodesmentioning

confidence: 99%

Nanoscale polypyrrole sensors for near-field electrochemical measurements

Venugopal

Venkatesh

Northcutt

et al. 2017

Sensors and Actuators B: Chemical

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“…where Q p , η p , η c , and F represent total charge accumulation during electropolymerization, electrons produced during polymerization, electrons consumed during polymerization, and the Faraday constant (Northcutt and Sundaresan (2014)). Thus, it is quite straightforward to expect that increasing the polymerization charge (or the mass of the polymer) would increase the number of redox sites.…”

Section: Mechanics Of Ion Transport In Ppy(dbs)mentioning

confidence: 99%

“…This phenomena would be observed in an atomically thin CP membrane. But, in a more realistic scenario, material and structural properties limit the redox site accessibility as would be observed at mesoscale thicknesses (Northcutt and Sundaresan, 2014). The experimental results presented in this article and the transfer-function based analysis are restricted to dependence of saturation kinetics on electrolyte concentration (or chemoelectrical potential Δ μ ) at constant thickness.…”

Section: Mechanics Of Ion Transport In Ppy(dbs)mentioning

confidence: 99%

Polypyrrole-based amperometric cation sensor with tunable sensitivity

Venugopal

Sundaresan

2015

Journal of Intelligent Material Systems and Structures

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This article presents a novel technique to quantify the kinetics of faradaic response in polypyrrole (doped with dodecylbenzenesulfonate) (PPy(DBS)) and its application in developing a cation sensor. This technique is based on the analysis of the impedance/admittance transfer function of PPy(DBS) and the representation of its reduction chronoameprometric response using system poles and residues. The results presented in this paper demonstrate that the pole of the transfer function is an intrinsic quantity and the residue corresponding to the system pole is an extrinsic quantity. The residue of the system pole for a redox-step potential is dependent on the concentration of cations and is observed to have linear dependence on electrolyte concentration ( R2 > 0.9). Thus, the residues can be used to accurately estimate the concentration of cations in an electrolyte solution and enables the use of PPy(DBS) as a high-precision cation sensor. The experimental investigation supporting this analysis demonstrates that the sensitivity of residue to concentration can be varied by equilibrating PPy(DBS) a priori in the cation containing solution of known concentration and by varying the morphology of PPy(DBS).

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“…However, a major limitation of using a bulk conducting polymer directly is insufficient exposure to the electrolyte solution due to the nonporous structure that is often formed. Previous efforts to engineer polymers into nanoporous structures have often involved multiple steps, where sacrificial materials used during polymerization are subsequently removed to introduce porosity …”

Section: Introductionmentioning

confidence: 99%

Electrochemically Nanostructured Polyvinylferrocene/Polypyrrole Hybrids with Synergy for Energy Storage

Tian

Mao

Brown

et al. 2015

Adv Funct Materials

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Unconjugated redox polymers, such as polyvinylferrocene (PVF), have rarely been used for energy storage due to their low intrinsic conductivity. Conducting polymers with conjugated backbones, though conductive, may suffer from insuffi cient exposure to the electrolyte due to the often formed nonporous structures. The present work overcomes this limitation via simultaneous electropolymerization of pyrrole and electroprecipitation of PVF on electrode surfaces. This synthesis method relies on the π-π stacking interactions between the aromatic pyrrole monomers and the metallocene moieties of PVF. This fabrication process results in a highly porous polymer fi lm, which enhances the ion accessibility to polypyrrole (PPy). PPy serves as a "molecular wire," improving the electronic conductivity of the hybrid and the utilization effi ciency of ferrocene. The PVF/PPy hybrid exhibited a specifi c capacitance of 514.1 F g −1 , which signifi cantly exceeds those of PPy (27.3 F g −1 ) and PVF (79.0 F g −1 ), respectively. This approach offers an alternative to nanocarbon materials for improving the electronic conductivity of polymer hybrids, and suggests a new strategy for fabricating nanostructured polymer hybrids. This strategy can potentially be applied to various polymers with π-conjugated backbones and redox polymers with metallocene moieties for applications such as energy storage, sensing, and catalysis.

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Phospholipid vesicles as soft templates for electropolymerization of nanostructured polypyrrole membranes with long range order

Cited by 19 publications

References 28 publications

Nanoscale polypyrrole sensors for near-field electrochemical measurements

Nanoscale polypyrrole sensors for near-field electrochemical measurements

Polypyrrole-based amperometric cation sensor with tunable sensitivity

Electrochemically Nanostructured Polyvinylferrocene/Polypyrrole Hybrids with Synergy for Energy Storage

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