Conductive Polymer Electrodes for Neural Prosthetic Applications

1985 ◽  
Vol 55 ◽  
Author(s):  
J. S. Foos ◽  
S. M. Erker
Keyword(s):  
Thin Films ◽  
Cyclic Voltammetry ◽  
Conductive Polymer ◽  
Neural Stimulation ◽  
Constant Current ◽  
Charge Storage ◽  
Neural Prosthetic ◽  
Polymer Electrodes ◽  
New Material ◽  
Phosphate Buffered Saline

ABSTRACTA variety of materials have been evaluated for use as electrodes for neural stimulation. In an effort to maximize the charge density on the electrode surface, faradaic stimulation electrodes have been investigated. Electrodes consisting of thin films of polypyrrole on Pt have been studied in phosphate buffered saline using cyclic voltammetry at 100 mV/s. The electrode capacity diminishes initially but stabilizes after ˜500 cycles. The electrodes were further evaluated in pulsing experiments using constant current, biphasic pulses. In these experiments, significant charge storage was observed only when using pulse widths greater than 5 ms. A modified polypyrrole was prepared using anthraquinone containing electrolyte. This new material is an apparent improvement over the polypyrrole previously studied.

Evaluation of Charge Injection Properties of Thin Film Redox Materials for use as Neural Stimulation Electrodes

1987 ◽  
Vol 110 ◽  
Author(s):  
Ellen M. Kelliher ◽  
Timothy L. Rose
Keyword(s):  
Thin Film ◽  
Cyclic Voltammetry ◽  
Film Thickness ◽  
Charge Injection ◽  
Neural Stimulation ◽  
Constant Current ◽  
Dramatic Improvement ◽  
Polypyrrole Films ◽  
Rh Oxide ◽  
Conductive Polypyrrole

AbstractThe charge injection limits of a variety of thin film redox materials considered for use as neural stimulation electrodes were evaluated under standardized conditions. Materials tested included the oxides of Ni, Ir, Rh, Ru, and Mn as well as conductive polypyrrole films. Electrodes with geometric areas of, ∼10–4 cm2were tested in bicarbonate buffered saline of pH 7.3. An electrochemically “safe” potential window was determined for each material by cyclic voltammetry. Charge injection capabilities within that window are evaluated with constant current 0.2 msec pulses. Pulse modes include anodic first and cathodic first biphasic pulses and monophasic cathodal pulses applied to electrodes held at an anodic bias. Pulsing from the anodic bias increased the charge limits for all the materials, but the most dramatic improvement was for Rh oxide. The highest charge injection values were obtained with oxides of iridium and rhodium and were of comparable value for the anodic bias mode of pulsing. Where the effect of film thickness was examined, the charge injection limit leveled off at 2–4 mC/cm2geometric as the film thickness increased.

Investigation of Polyoxometalate-(Poly)pyrrole Heterogeneous Nanostructures as Cathodes for Rechargeable Magnesium-Ion Batteries

2018 ◽  
Author(s):  
Hakeem K. Henry ◽  
Sang Bok Lee
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Photoelectron Spectroscopy ◽  
Active Material ◽  
Conductive Polymer ◽  
Current Collector ◽  
Constant Current ◽  
Anodized Aluminum ◽  
Transmission Electron ◽  
Pyrrole Monomer

The PMo<sub>12</sub>-PPy heterogeneous cathode was synthesized electrochemically. In doing so, the PMo<sub>12</sub> redox-active material was impregnated throughout the conductive polymer matrix of the poly(pyrrole) nanowires. All chemicals and reagents used were purchased from Sigma-Aldrich. Anodized aluminum oxide (AAO) purchased from Whatman served as the porous hard template for nanowire deposition. A thin layer of gold of approximately 200nm was sputtered onto the disordered side of the AAO membrane to serve as the current collector. Copper tape was connected to the sputtered gold for contact and the device was sealed in parafilm with heat with an exposed area of 0.32 cm<sup>2</sup> to serve as the electroactive area for deposition. All electrochemical synthesis and experiments were conducted using a Bio-Logic MPG2 potentiostat. The deposition was carried out using a 3-electrode beaker cell setup with a solution of acetonitrile containing 5mM and 14mM of the phosphomolybdic acid and pyrrole monomer, respectively. The synthesis was achieved using chronoamperometry to apply a constant voltage of 0.8V vs. Ag/AgCl (BASi) to oxidatively polymerize the pyrrole monomer to poly(pyrrole). To prevent the POM from chemically polymerizing the pyrrole, an injection method was used in which the pyrrole monomer was added to the POM solution only after the deposition voltage had already been applied. The deposition was well controlled by limiting the amount of charge transferred to 300mC. Following deposition, the AAO template was removed by soaking in 3M sodium hydroxide (NaOH) for 20 minutes and rinsed several times with water. After synthesis, all cathodes underwent electrochemical testing to determine their performance using cyclic voltammetry and constant current charge-discharge cycling in 0.1 M Mg(ClO<sub>4</sub>)<sub>2</sub>/PC electrolyte. The cathodes were further characterized using scanning electron microscopy (SEM), transmission electron microscopy (TEM), scanning transmission electron microscopy (STEM), and x-ray photoelectron spectroscopy (XPS).

Endgroup and Sidechain Functionalization of Surface-Initiated ROMP Thin Films: Progress Towards ROMP-Based Molecular Wires

2018 ◽  
Author(s):  
Nicholas Marshall
Keyword(s):  
Thin Films ◽  
Contact Angle ◽  
Cyclic Voltammetry ◽  
Polymer Films ◽  
Conjugated Polymer ◽  
Ring Opening ◽  
Molecular Wires ◽  
Metathesis Polymerization ◽  
Cross Metathesis ◽  
Active Ester

A set of experiments in surface-initiated ring-opening metathesis polymerization, including end-functionalization of growing brushes and contact angle/cyclic voltammetry measurements. We report preparation and CV of two different conjugated polymer films, and several endgroup and sidechain functionalization experiments using cross-metathesis and active ester substitution.<br>

scholarly journals Integrated Polypyrrole Flexible Conductors for Biochips and MEMS Applications

2012 ◽  
Vol 2012 ◽  
pp. 1-5 ◽  
Author(s):  
Rakefet Ofek Almog ◽  
Hadar Ben-Yoav ◽  
Yelena Sverdlov ◽  
Tsvi Shmilovich ◽  
Slava Krylov ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Aspect Ratio ◽  
Seed Layer ◽  
Conductive Polymer ◽  
Sensors And Actuators ◽  
Flexible Sensors ◽  
Planar Structures ◽  
Polymeric Substrates ◽  
Seed Layers ◽  
Structural Polymers

Integrated polypyrrole, a conductive polymer, interconnects on polymeric substrates were microfabricated for flexible sensors and actuators applications. It allows manufacturing of moving polymeric microcomponents suitable, for example, for micro-optical-electromechanical (MOEMS) systems or implanted sensors. This generic technology allows producing “all polymer” components where the polymers serve as both the structural and the actuating materials. In this paper we present two possible novel architectures that integrate polypyrrole conductors with other structural polymers: (a) polypyrrole embedded into flexible polydimethylsiloxane (PDMS) matrix forming high aspect ratio electrodes and (b) polypyrrole deposited on planar structures. Self-aligned polypyrrole electropolymerization was developed and demonstrated for conducting polymer lines on either gold or copper seed layers. The electropolymerization process, using cyclic voltammetry from an electrolyte containing the monomer, is described, as well as the devices’ characteristics. Finally, we discuss the effect of integrating conducting polymers with metal seed layer, thus enhancing the device durability and reliability.

Poly(O-methoxyaniline) thin films: Cyclic voltammetry study

1999 ◽  
Vol 74 (13) ◽  
pp. 3009-3015 ◽  
Author(s):  
Sharmila Patil ◽  
M. A. More ◽  
P. P. Patil
Keyword(s):  
Thin Films ◽  
Cyclic Voltammetry

Understanding and Calibration of Charge Storage Mechanism in Cyclic Voltammetry Curves

2021 ◽  
Author(s):  
Xiangjun Pu ◽  
Dong Zhao ◽  
Chenglong Fu ◽  
Zhongxue Chen ◽  
Shunan Cao ◽  
...  
Keyword(s):  
Cyclic Voltammetry ◽  
Charge Storage ◽  
Storage Mechanism ◽  
Charge Storage Mechanism

Charge Storage Effects in Si Nanocrystals Embedded in SiO2 Thin Films

2001 ◽  
Vol 80-81 ◽  
pp. 243-248 ◽  
Author(s):  
O. González-Varona ◽  
B. Garrido ◽  
A. Pérez-Rodríguez ◽  
Caroline Bonafos ◽  
Josep Montserrat ◽  
...  
Keyword(s):  
Thin Films ◽  
Charge Storage ◽  
Si Nanocrystals ◽  
Storage Effects

scholarly journals Hybrid Chemomechanical Promotion of PEDOT Adhesion onto Flexible Microelectrode Arrays for Chronic Neural Stimulation

2020 ◽  
Author(s):  
Mohammad Hossein Mazaheri Kouhani ◽  
Alexander Istomin ◽  
Proyag Datta ◽  
Neil H. Talbot
Keyword(s):  
Diazonium Salt ◽  
Covalent Binding ◽  
Microelectrode Arrays ◽  
Electrochemical Treatment ◽  
Neural Stimulation ◽  
Adhesion Promoter ◽  
Neural Prosthetic ◽  
Long Term Stability ◽  
Mechanical Adhesion

Advances in neural prosthetic technologies demand ever increasing novelty in material composition to enhance the mechanical and electrochemical properties of existing microelectrode arrays. Conductive polymers present advantages such as mechanical flexibility, outstanding biocompatibility, remarkable electrical properties and, most of all, cellular agreement. However, for long-term chronic applications, they fall short in their electrochemical endurance and mechanical adhesion to their substrate materials. Multiple electrochemical approaches have been investigated to improve the adherence of Poly(3,4-ethylenedioxythiophene) (PEDOT) to underlying metallic thin films. In this work, an electrochemical treatment of diazonium salt on platinum microelectrodes is incorporated as an electrochemical adhesion promoter for PEDOT and it is further combined with using the highly microporous geometry of Platinum Grey (Pt-Grey); a technology developed by Second Sight Medical Products Inc (SSMP). The intertwined mechanical integration of Pt-Grey and PEDOT molecules together with the covalent binding agency of diazonium salt demostrate a composite coating technology with long-term stability of more than 452 days while providing >70× enhancement to the interfacial capacitive impedance.

scholarly journals Reevaluation of Performance of Electric Double-layer Capacitors from Constant-current Charge/Discharge and Cyclic Voltammetry

2016 ◽  
Vol 6 (1) ◽  
Author(s):  
Anis Allagui ◽  
Todd J. Freeborn ◽  
Ahmed S. Elwakil ◽  
Brent J. Maundy
Keyword(s):  
Cyclic Voltammetry ◽  
Double Layer ◽  
Time Domain ◽  
Electric Double Layer ◽  
Constant Current ◽  
Step Response ◽  
Current Voltage ◽  
The Time Domain ◽  
Double Layer Capacitors ◽  
Electric Double Layer Capacitors

Abstract The electric characteristics of electric-double layer capacitors (EDLCs) are determined by their capacitance which is usually measured in the time domain from constant-current charging/discharging and cyclic voltammetry tests, and from the frequency domain using nonlinear least-squares fitting of spectral impedance. The time-voltage and current-voltage profiles from the first two techniques are commonly treated by assuming ideal S s C behavior in spite of the nonlinear response of the device, which in turn provides inaccurate values for its characteristic metrics. In this paper we revisit the calculation of capacitance, power and energy of EDLCs from the time domain constant-current step response and linear voltage waveform, under the assumption that the device behaves as an equivalent fractional-order circuit consisting of a resistance R s in series with a constant phase element (CPE(Q, α), with Q being a pseudocapacitance and α a dispersion coefficient). In particular, we show with the derived (R s , Q, α)-based expressions, that the corresponding nonlinear effects in voltage-time and current-voltage can be encompassed through nonlinear terms function of the coefficient α, which is not possible with the classical R s C model. We validate our formulae with the experimental measurements of different EDLCs.

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