The field of electroactive polymers

The fundamental observation is that even a rather thick polymer film, where most of the redox sites are 100-10 000 nm away from the metal surface, may be electrochemically oxidized or reduced. According to the classical theory of simple electron-transfer reaction, when the reactants get to the Helmholtz plane close to the electrode surface, the electrons can tunnel over the short 

Impedance analysis of electrochemically active polymer films 

Electrochemical impedance spectroscopy allows the investigation of charge-and mass-transport kinetics and charging processes taking place within the analyzed material and at the active interfaces of the system. In recent years AC impedance technique has become a primary method of investigation of modified electrodes, and it has proven to be a powerful tool for the characterization of electrochemically active polymer films. 

Modeling an electrochemical interface by the equivalent circuit (EC) representation approach has been exceptionally popular in studies of electrodes modified with polymer membranes, although an analytical approach based on transport equations derived from irreversible thermodynamics was also attempted [6,7]. ECs are typically composed of numerous ideal electrical components, which attempt to represent the redox electrochemistry of the polymer itself, its highly developed morphology, the interpenetration of the electrolyte solution and the polymer matrix, and the extended electrochemical double layer established between the solution and the polymer with variable localized properties (degree of oxidation, porosity, conductivity, etc.). 

transport of electrons between the electrode/film and film/solution interfaces 

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Vinogradov AM (2008) Accomplishments and future trends in the field of electroactive polymers. Proc SPIE 6927 69270M... 

The intensive investigation of polyacetylene s electrical, magnetic, and optical properties generated considerable enthusiasm for the field of electroactive polymers and, as the limitations of polyacetylene became clear, many research groups sought alternative materials which would combine interesting electrical properties with more acceptable stability and processing characteristics. 

The normal pulse voltammetry (NPV) technique has been used largely by Oyama and coworkers to determine Z>cr values for charge percolation through the polymer and the kinetic parameters and a for charge injection at the support/film interface. The technique has been used quite extensively as a routine tool in electroanalytical chemistry, but surprisingly it has not been used extensively in the field of electroactive polymers. 

In order to interpret the eleetromechanical results, the performance of IPMCs is often reported alongside of a variety of characteristics such as tire capacitance of the actuator, current during the operation cycle, charge accumulated by the time of maximum displacement/blocking force, conductivity of the electrodes, viscoelasticity of the materials, etc. Finding out how all these parameters relate to the electromechanical response of IPMCs is a subject of ongoing research in the field of electroactive polymers. 

In Chapter 9, Bartlett and Cooper discuss the applications of electroactive polymers in bioelectrochemistry and bioelectronics. This is a very exciting and rapidly developing field, and it is proper that the volume includes this topic. Electroactive polymer materials will feature strongly in future developments in this area. Again Bartlett and Cooper have made major contributions in this field. 

In Chapter 10, Leech discusses the analytical applications of polymer-modified electrodes. In Chapter 11, the analytical theme is continued and again, Iwuoha and Smyth survey the applications of electroactive polymers in electroanalytical chemistry. In this case the important area of biosensors is examined. The areas described in these chapters have attracted significant research activity in recent years, and the material presented in these chapters is timely, and is written by well known and experienced practitioners in the field. 

The first problem arises from deformability. It is impossible to prepare same numbers of input to degrees of freedom of the body, since the deformable machines like gel robots have virtually infinite degrees of freedom. In the case of electroactive polymers, the materials require driving electrodes. This applies to any kinds of materials driven by electric fields. The body becomes full of wires if we prepare driving electrodes as many as possible. A method to reduce the numbers of input effectively is required without decreasing the controllability. 

The field of electroactive transducers has reached a certain maturity that they can be used in establishing flmctional devices. The object of this chapter is to review configurations for flmctional devices articulated with EAP actuators, or combination of actuators and sensors, which can be considered as the devices. It is our tmder-standing that a device is an invention or a means such as a mechanical, electrical, or a combination of both, for a particular purpose. A transducer is a device which converts one form of energy into another, e.g., electrical into mechanical and vice versa. This follows that EAP transducers refer to the actuators, sensors, and energy harvesters made of electroactive polymers. 

Conducting polymers based on polymer chains with conjugated double bonds are electroactive materials that have found widespread use also in the field of chemical sensors [11-41], Oxidation of the conjugated polymer backbone is accompanied by anion insertion or cation expulsion, as follows ... 

The field of molecular electronics may be considered to encompass much more than molecular electronic devices. In its broadest context, molecular electronics may be regarded as simply the application of molecules, primarily organic molecules, to electronics. This definition would include such areas as liquid crystalline materials, piezoelectric materials such as poly(vinylidine fluoride), chemically sensitive field-eflFect transistors (CHEMFET), and the whole range of electroactive polymers. These applications are beyond the scope of this book and are covered in other reviews 34, 33). However, given the basic tenet of molecular electronics, namely, the ability to engineer and assemble molecular structures into a useful device, the broader definition raises the question of whether organic molecules can be specifically assembled or engineered for unique applications in electronics. 

Peter Teasdale, Ph.D., is a senior lecturer in environmental chemistry at Australian Rivers Institute, Griffith University Gold Coast Campus. His current research interests include in situ sensors for metals and nutrients, natural, recycled and potable water quality, microbial toxicology, and sediment biogeochemistry. Peter is the current chair of the Royal Australian Chemical Institute Environment Division. He has published over 40 refereed publications. Coauthoring this book reflects his interest in the field of conducting electroactive polymers, the area in which he completed his Ph.D. in 1993 at the University of Wollongong. 

The field of conjugated, electrically conducting, and electroactive polymers continues to grow. Since the publication of the second edition of the Handbook of Conducting Polymers in 1998, we have witnessed hroad advances with significant developments in both fundamental understanding and applications, some of which are already reaching the marketplace. 

There has been growing interest in the field of supercapacitors due to their possible applications in medical devices, electrical vehicles, memory protection of computer electronics, and cellular communication devices. Their specific energies are generally greater than those of electrolytic capacitors and their specific power levels are higher than those of batteries. Supercapacitors can be divided into redox supercapacitors and electrical double layer capacitors (EDLCs). The former uses electroactive materials such as insertion-type compounds or conducting polymers as the electrode, while the latter uses carbon or other similar materials as the blocking electrode. 

Conclusively, there still remains a lot of research to be done in the field of the electroactive polymer materials. However, as we have a solid understanding of the fundamentals, the research will be focused more on the practical applications. Here we have only demonstrated a few. Given the favorable biocompability of the materials, there is a great potential for a broad spectrum of biomimetic applications in the future. 

An electrical field in the form of an external stimulus offers numerous advantages (e.g., availability of equipment). This form of an external stimulus also allows for precise control over the magnitude of the current, the duration of electrical pulses, and the interval between pulses. Poly(vinyl alcohol) (PVA) is one of the well-known electroactive polymers with good thermal stability, chemical resistance, water permeability, and biocompatibility. Xia et al. demonstrated electric-field induced actuation of PVA microfibers (Fig. 5.4.5) [17]. 

In the past two decades the biomedical field has witnessed an exponential increase in the utilization of synthetic polymers and plastics-based products in various clinical and diagnostic areas. Electroactive polymers represent an interesting class of synthetic polymers that by virtue of their ability to function as electrochemical, electromechanical, and electro-optical transducers, can be utilized to interface between the external environment and the biological system both in vitro and in vivo. 

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