Electrically conducting polymers, potential applications

Electrically conductive polymers are perspective materials in modern technologies because of their potential applications as chemical sensors, catalysts, microelectronic devices, etc. [1]. The interest to new hybrid nanostructured materials based on polymer matrix with poly-7t-conjugated bonds and noble metals nanoparticles constantly increases. This is reasoned by a wide spectrum of new optical and electrophysical properties [2]. 

Spectroelectrochemistry is one of the many facets of photoelectroanalytical chemistry. It can be used for numerous purposes in solving the mechanisms of electrochemical processes but especially with electrically conducting polymers it shows its main advantages. The original drive to study conductive polymers arose from the applications anticipated in the energy storage, but these polymers are also interesting from the analytical point of view as potential sensor materials. 

Many polymers and most PMC show no or only comparatively low electrical conductivity, which limits application of electromagnetic test methods. One of the main exceptions is CFRP. The continuous network of carbon fibers in CFRP allows for electrical resistance measurements, eg, based on the four-probe method. Electrical potential (101) or resistance methods are used in fracture mechanics to detect delaminations (102) and to monitor damage in CFRP (103). Whether the application of electrodes is nondestructive depends on the intended use. 

Nontoxic Citrates Nontoxic citrate plasticizers derived from natural citric acid, such as triethyl citrate (TC), tributyl citrate (TBC), acetyl triethyl citrate (ATC), acetyl tributyl citrate (ATBC), and triacetine, have been shown to be effective plasticizers for PLA [27-29]. Some gas permeability tests have been performed to assess the potential use of PLA and nontoxic citrate plasticizer blends in food packaging and other applications. The effect of ATBC on PLA barrier properties was studied by Coltelli et al. [30] using PLA mixed with ATBC (10-35 wt%), followed by compression molding. Yu et al. [31] blended PLA/ATBC mixmres with carbon black (CB) to form electrically conductive polymer composites. Fourier transform infrared (FTIR) experiments revealed that the interaction between the PLA/ATBC matrix and the CB filler was increased by the addition of ATBC. Water vapor permeability values decreased with an increase in ATBC content (at constant CB levels). For example, at 30wt% CB, the WVP of the PLA decreased from 0.66 x 10 kgm/(msPa) (at 0% ATBC) to 0.10 X 10 kgm/(msPa) with the addition of 30% ATBC. 

Electrical properties of materials are described by their behavior in the presence of an electric field. Basically, the response of any material to an electric field can be separated into two main parts dielectric response and electrical conduction. Polymer-based materials with good conduction properties have been the subject of fundamental scientific interest due to their tremendous potential in various applications (Gul 1996). Even though most polymeric materials are not conductors of electricity, they are easy to fabricate into complex shapes at a reduced expense. In particular, thermoplastics are moldable or extrudable into various shapes and sizes (Thomas et al. 2015). Besides this, the specific weight of industrial standard... 

Electrically conductive polymer nanocomposites are widely used especially due to their superior properties and competitive prices. It is expected that as the level of control of the overall morphology and associated properties increases we will see an even wider commercialisation on traditional and totally novel applications. In this section we have discussed the basic principles of the percolation theory and the different types of conduction mechanisms, outlined some of the critical parameters of controlling primarily the electrical performance and we have provided some indications on the effect such conductive fillers have on the overall morphology and crystallisation of the nanocomposite. The latter becomes even more critical if we take into consideration that modem nanosized fillers offer unique potential for superior properties at low loadings (low percolation thresholds) but have a more direct impact on the morphology of the system. Furthermore we have indicated that similar systems can have totally different behaviour as the preparation methods, the chain conformation and the surface chemistry of the fillers will have a massive... 

Meador, M.A. Gaier, J.R. Good, B.S. Sharp, G.R. Meador, M.A., "A Review of Properties and Potential Aerospace Applications of Electrically Conducting Polymers", Internal Report National Aeronautics and Space Administration, Lewis Research Center, Cleveland, OH, USA, pp. 1-21 (1989). 

The rate and the degree of reaction of an electrically conductive polymer in repeated redox reaction are important factors in application of the polymer. The fast response of the polymer to an external stimulation may find uses in a sensor or a display. The reaction rate must depend on the mobility of ions in the polymer toward the reactive sites under an applied potential. The degree of the reaction in the cycled oxidation-reduction process predicts applicability of the electrically conductive materials in battery, sensor, transistor, solar cells, etc(6,7). 

The most promising candidate to fill these criteria was, surprisingly, an electrically conductive polymer material known as polythiophene. Such polymers have always had great commercial potential because of their unusual ability (for a plastic) to provide a path for electrons, but they had not found any wide commercial applications to that point. 

Electrically conducting polymers have been a subject of extensive studies in view of both academic interest and potential technological applications. This chapter describes the synthesis and properties of electrically conducting polymers and their applications as functional materials, such as electrode materials for secondary batteries, photoactive materials for photovoltaic devices, electrochromic materials, and materials for use in organic electroluminescent devices. 

In recent several years, super-capacitors are attracting more and more attention because of their high capacitance and potential applications in electronic devices. The performance of super-capacitors with MWCNTs deposited with conducting polymers as active materials is greatly enhanced compared to electric double-layer super-capacitors with CNTs due to the Faraday effect of the conducting polymer as shown in Fig. 9.18 (Valter et al., 2002). Besides those mentioned above, polymer/ CNT nanocomposites own many potential applications (Breuer and Sundararaj, 2004) in electrochemical actuation, wave absorption, electronic packaging, selfregulating heater, and PTC resistors, etc. The conductivity results for polymer/CNT composites are summarized in Table 9.1 (Biercuk et al., 2002). 

---