Conducting polymers molecular level

Here we introduce a personal point of view about the interactions between conducting polymers and electrochemistry their synthesis, electrochemical properties, and electrochemical applications. Conducting polymers are new materials that were developed in the late 1970s as intrinsically electronic conductors at the molecular level. Ideal monodimensional chains of poly acetylene, polypyrrole, polythiophene, etc. can be seen in Fig. 1. One of the most fascinating aspects of these polymeric... 

The presence of polymer, solvent, and ionic components in conducting polymers reminds one of the composition of the materials chosen by nature to produce muscles, neurons, and skin in living creatures. We will describe here some devices ready for commercial applications, such as artificial muscles, smart windows, or smart membranes other industrial products such as polymeric batteries or smart mirrors and processes and devices under development, such as biocompatible nervous system interfaces, smart membranes, and electron-ion transducers, all of them based on the electrochemical behavior of electrodes that are three dimensional at the molecular level. During the discussion we will emphasize the analogies between these electrochemical systems and analogous biological systems. Our aim is to introduce an electrochemistry for conducting polymers, and by extension, for any electrodic process where the structure of the electrode is taken into account. 

Even when they have a partial crystallinity, conducting polymers swell and shrink, changing their volume in a reverse way during redox processes a relaxation of the polymeric structure has to occur, decreasing the crystallinity to zero percent after a new cycle. In the literature, different relaxation theories (Table 7) have been developed that include structural aspects at the molecular level magnetic or mechanical properties of the constituent materials at the macroscopic level or the depolarization currents of the materials. 

XV. CONDUCTING POLYMERS AS THREE-DIMENSIONAL ELECTRODES AT THE MOLECULAR LEVEL... 

The search for flexible, noncorrosive, inexpensive conductive materials has recently focused on polymeric materials. This search has increased to include, for some applications, nanosized fibrils and tubes. The conductivity of common materials is given in Figure 19.1. As seen, most polymers are nonconductive and, in fact, are employed in the electronics industry as insulators. This includes PE and PVC. The idea that polymers can become conductive is not new and is now one of the most active areas in polymer science. The advantages of polymeric conductors include lack of corrosion, low weight, ability to lay wires on almost a molecular level, and ability to run polymeric conductive wires in very intricate and complex designs. The topic of conductive carbon nanotubes has already been covered (Section 12.17). 

It should be mentioned that the defined interaction of dextran sulfate with amino functions is not only applied for the design of structures on the su-permolecular level but also on the molecular level. Thus, a preferred handed helical structure was induced into the polyaniline main chains by chemical polymerisation of achiral aniline in the presence of dextran sulfate as a molecular template. This affords a novel chemical route for the synthesis of chiral conducting polymers [158]. 

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