Typical Conducting Polymer Nanostructures

Despite significant efforts, the types of conducting polymers are limited to PHT, PPy, PA, PANI, PEDOT, polyphenylenes (PP), poly(p-phenylene vinylene) (PPV), and a few others. Here, some significant results on PANI, PPy, and PEDOT conducting polymers and their nanostructures are briefly reviewed as follows. 

Alan G. MacDiarmid and his colleagues reported that aniline monomer in an acid aqueous solution (e.g., 1.0 M HCl) could be chemically oxidized by APS to form a green powder with a conductivity as high as 3 S cm, which was latter called the emeraldine salt (ES) form of PANI [46]. PANI is easy to synthesize and at a low cost and has great potential for modification of the molecular structure, and undergoes 

Till date, liquid-crystalline phases [51], colloidal particles [52], and structure-directing molecules [53[ as the soft-template have been employed to synthesize PANI nanostructures. Based on the traditional synthesis method of PANI, in particular, some simple approaches such as interfacial polymerization [54], mixed reactions [55], dilute polymerization [56] and ultrasonic irradiation [57] have also been employed to synthesize PANI. The interfacial polymerization method only allows the oxidative polymerization of aniline to take place at the interface of the organic/water phases and the product directly enters into the water phase, which could facilitate environmentally friendly processing. 

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FIGURE 7.4 Schematic drawing illustrating the electrospinning process to make conducting polymer nanostructures. Typically, a potential of several thousand volts is applied to overcome the surface tension. 

FIGURE 16.4 I-V characteristics of iodine doped PA nanofiber. Znsef shows scanning force microscope image of PA nanofiber on top of Pt electrodes (with 100 nm separation). Typical diameter of PA nanofiber is 16-20 mn (From Park, J.G., et al. Synth. Met., 119, 53, 2001 and Park, J.G., Electrical transport properties of conducting polymer nanostructures Polyacetylene nanofiber, polypyrrole nanotube/nanowire, Ph.D. thesis, Seoul National University, Seoul, 2003.). 

In addition to nanostructural properties of the conducting polymer, considerable influence on actuation behavior has been demonstrated due to the choice of electrolyte. This has included properties of the solvent employed, and crucially the size of doping ions and their interaction with the conducting polymer. As mentioned above, PPy films doped with moderately small anions (e.g. CP) lead to actuation driven by anion movement. By contrast, it is generally found that the inclusion of a large dopant anion (e.g. DBS) within PPy leads to cation-driven actuation, typically when a smaller cation is employed (e.g. Na ). However, it is not always a simple matter of predicting which movement, anion or cation, will predominate for a particular electrolyte system, and for a particular type of... 

The book starts with an introductory chapter about conductive polymers. For those who are familiar with nanotechnology, this chapter is a guiding star and for polymer scientists, it is a reminder that from where we have started. The two next chapters are typical ones to introduce the realms of nanostructured conductive polymers. Polyaniline is considered as a prototype and among most popular conductive polymers. Chapter 3 discusses some interesting features in surface studies of conductive polymer, while surface analysis is always a key concept in the realm of nanotechnology. 

Two-dimensional nanostructures have two dimensions outside of the nanometric size range, such as nanoplates, nanosheets, and nanodisks. Graphene is a typical two-dimensional film, which is composed of a one-atom-thick planar sheet of sp -bonded carbon atoms that are densely packed into a honeycomb crystal lattice. This material exhibits a high electrical conductivity, a high surface area of over 2600 m g , an elevated chemical tolerance, and a broad electrochemical window. Therefore, they were used to form two-dimensional nanocomposites with polymers. The graphene not only increases the electrical conductivity of the polymer, but also enhance its mechanical stability. Conducting polymers with various hierarchical structures have been deposited on... 

Polymer solar cell Typically the p-type conducting polymer can be applied as hole transporting material, and the mostly used is PEDOTPSS in polymer solar cell. This material has been studied thoroughly and fabricated into one-dimensional nanostructured network... 

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