Electroactive composites applications

One option to develop artificial muscles is the use of electroactive polymers (EAPs) or electroactive composite structures based on polymers. These materials or stmctures are able to convert electrical energy into mechanical energy. Different types of materials and stmctores with different properties are explored for many applications (Bar-Cohen, 2004). 

In potentiometry the potential of an electrochemical cell is measured under static conditions. Because no current, or only a negligible current, flows while measuring a solution s potential, its composition remains unchanged. For this reason, potentiometry is a useful quantitative method. The first quantitative potentiometric applications appeared soon after the formulation, in 1889, of the Nernst equation relating an electrochemical cell s potential to the concentration of electroactive species in the cell. ... 

Willner and coworkers demonstrated three-dimensional networks of Au, Ag, and mixed composites of Au and Ag nanoparticles assembled on a conductive (indium-doped tin oxide) glass support by stepwise LbL assembly with A,A -bis(2-aminoethyl)-4,4 -bipyridinium as a redox-active cross-linker.8 37 The electrostatic attraction between the amino-bifunctional cross-linker and the citrate-protected metal particles led to the assembly of a multilayered composite nanoparticle network. The surface coverage of the metal nanoparticles and bipyridinium units associated with the Au nanoparticle assembly increased almost linearly upon the formation of the three-dimensional (3D) network. A coulometric analysis indicated an electroactive 3D nanoparticle array, implying that electron transport through the nanoparticles is feasible. A similar multilayered nanoparticle network was later used in a study on a sensor application by using bis-bipyridinium cyclophane as a cross-linker for Au nanoparticles and as a molecular receptor for rr-donor substrates.8... 

The second important quantity, the half-wave potential can be a measure of the standard free energy change (AG°) or free energy of activation AG ) associated with the electrolytic process. The value of the half-wave potential depends on the nature of the electroactive species, but also on the composition of the solution in which the electrolysis is carried out. If the composition of the solution electrolysed, consisting of the electroactive substance and a proper supporting electrolyte, often buffered, is kept constant, it is possible to compare the half-wave potentials of various substances. When the mechanism of the electrode process is similar for all compounds compared, the halfwave potential can be considered to be a measure of the reactivity of the compound towards the electrode. Hence the half-wave potentials are physical constants that characterize quantitatively the electrolysed compound, or the composition of the electrolyzed solution. In the application of polarography to reaction kinetics the half-wave potentials are of importance both for slow and fast reactions. For slow reactions a large difference in half-wave potentials makes a simultaneous determination of several components of the reaction mixture possible. In... 

Obtaining information on the composition, structure, etc., of solid materials using voltammetric and related techniques can be performed by (1) recording the response of the material attached to an inert electrode and immersed into a suitable electrolyte or (2) recording the modification of the response of an electroactive probe in the electrolyte solution in contact with the material-modified electrode. In addition, the electrochemical response of such systems under the application of optical or magnetic inputs can also be used. 

The high level of interest in potential applications of polyacetylene (1), (CH)X, is tempered in many instances by the prospects of intractability and poor physical and mechanical properties. In an attempt to mitigate such undesirable characteristics, we have attempted to prepare copolymers and blends (or composites) in which the electroactive component is (CH)X. 

A.S. Singha, B.S. Kaith, and A.J. Khanna, "Application of waste bio-mass in PR-F based composites and study of their properties" Second Interrmtional Conference on Electroactive Polymers, ICEP-2007,19-24 February, 2007, Goa. 

This chapter presents the outcome of the research done for over a decade pertaining to the study of biomaterials, namely, the investigation and understanding of various physical mechanisms, their potential application, and future direction. The research addressed the basic problems to be resolved regarding the electroactivity in natural gums whose chemical characterization/composition was known. The author along with his student also identified their scope of application. Biomaterials are more compelling than conventional materials due to their non-toxicity, eco-friendly nature, and superior cost-effectiveness. 

In the case of (a), the zero-dimensional (0-D) nanostructure is composed of nanoparticles whose fabrication requires the control of more than merely their diminutive size. For any practical applications such as electroactive components in electrodes, the processing conditions must be controlled so that the resulting nanoparticles have the following characteristics (a) identical size of aU particles (also referred to as monosized or quasi-monosized), (b) identical shape or morphology, and (c) identical or at least very similar chemical composition and crystal structure. Single crystalline nanoparticles are often referred to in the literature as nanocrystals. When the characteristic dimensions of nanoparticles are sufficiently small and quantum effects are observed, these nanoparticles are commonly... 

An electrochemically heterogeneous electrode is one where the electrochemical activity varies over the surface of the electrode. This broad classification encompasses a variety of electrode types [1, 2] including microelectrode arrays, partially blocked electrodes, electrodes made of composite materials, porous electrodes and electrodes modified with distributions of micro- and nanoscale electroactive particles. In this chapter, we extend the mathematical models developed in the previous chapter, in order to accurately simulate microelectrode arrays. Fbrther, we explore the applications of a number of niche experimental systems, including partially blocked electrodes, highly ordered pyrolytic graphite, etc., and develop simulation models for them. 

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