Poly polyaniline nanofibers

Figure 2.13 Schematic illustration of the process of fabricating a porous PANI-NF film by a galvanostatic method using porous poly(styrene-block-2-vinylpyridine) diblock copolymer films as templates. (Reprinted with permission from Langmuir, One-Step Route to the Fabrication of Highly Porous Polyaniline Nanofiber Films by Using PS-b-PVP Diblock Copolymers as Templates by X. Li, S. Tian, Y. Ping et ai, 2 , 2 , 9393-9397. Copyright (2005) American Chemical Society)...

Z. Hu, J. Xu, Y. Tian, R. Peng, Y. Xian, Q. Ran, and L. Jin, Layer-by-layer assembly of polyaniline nanofibers/poly(acrylic acid) multilayer film and electrochemical sensing, Electrochim. Acta, 54, 4056 061 (2009). 

M. Deka, A. K. Nath, and A. Kumar, Effect of dedoped (insulating) polyaniline nanofibers on the ionic transport and interfacial stability of poly(vinylidene fluoride-hexafluoropropylene) based composite polymer electrolyte membranes, J. Membrane Set, ill, 188-194 (2009). 

Dielectric constant data have been reported on several unreinforced polymers, including polyimides [19-21], silicones [22], epoxy resins [23], polyurethanes [23], polyaniline nanofibers [16, 17], zirconium nanocomposites [24], cross-linked polyethylene [15], low-density polyethylene [22], doped polyimines [19], polyimide-3-zirconium propoxide nanocomposites [24], poly linu-naphthyl ether [30], and cross-linked polyethylene-polyethylene polyacrylate acid blends [15]. 

Figure 4.23 (a) Typical electrical responses of PANI/PMMA composite nanofibers to TEA vapors of different concentrations (doping acid TSA). (b) Sensing magnitude of PANI/PMMA composite nanofibers with different diameters as a function of the concentration of TEA vapor. Concentration ofelectrospun PMMA solution (a) 0.32 g ml and (b) 0.18 g ml (Reprinted with permission from Sensors and Actuators B., Gas sensing properties of a composite composed ofelectrospun poly(methyl methacrylate) nanofibers and in situ polymerized polyaniline byS.Ji, Y. Li and M. Yang, 133, 644-649. Copyright (2008) Elsevier Ltd)... 

S. Ji, Y. Li, and M. Yang, Gas sensing properties of a composite composed of electrospun poly(methyl methacrylate) nanofibers and in situ polymerized polyaniline. Sensors Actuat. B, 133, 644-649 (2008). 

There are various methods to synthesize polymer nanostructures, i.e., template synthesis, chiral reactions, self-assembly, interfacial polymerization and electrospinning. Recent developments in conducting polymer nanotubes and nanofibers were summarized by Long et al. Different preparation methods, physical properties, and potential applications of one-dimensional nanostructures of conjugated polyaniline (PANI), pol5 3nrole (PPy) and poly (3, 4-ethylenediox3d hiophene) (PEDOT) were discussed. 

To improve PANI processability, the first approach to obtain polyaniline doped with camphorsulfonic acid (PANI-CSA) and doped nanofibers blended with common pol5miers by electrospinning was done by MacDiarmid s group. In another study a nonwoven mat was obtained by using a PANI/poly(ethylene oxide) (PEO) solution dissolved in chloroform. By controlling the ratio of PANI to PEO in the blend, fibers with conductivity values comparable to that of PANI-CSA/PEO cast films were produced. 

Self-doped polyanilines are advantageous due to properties such as solubility, pH independence, redox activity and conductivity. These properties make them more promising in various applications such as energy conversion devices, sensors, electrochromic devices, etc. (see Chapter 1, section 1.6). Several studies have focused on the preparation of self-doped polyaniline nanostructures (i.e., nanoparticles, nanofibers, nanofilms, nanocomposites, etc.) and their applications. Buttry and Tor-resi et al. [51, 244, 245] prepared the nanocomposites from self-doped polyaniline, poly(N-propane sulfonic acid, aniline) and V2O5 for Li secondary battery cathodes. The self-doped polyaniline was used instead of conventional polyaniline to minimize the anion participation in the charge-discharge process and maximize the transport number of Li". In lithium batteries, it is desirable that only lithium cations intercalate into the cathode, because this leads to the use of small amounts of electrolyte... 

Polyaniline-based nanofibers with diameter below 30 nm were obtained with the electrospinning process [304] which is suitable not only for conjugated polymers, but also for non conjugated, water soluble polymers such as poly-ethylen oxide (PEO), polyvinyl alcohol (PVA) and poly-lactic acid (PLA). In fact, one of the... 

Nanofibers of conducting polymers such as those spun from polyaniline (PANi) are particularly well suited for use in conductivity sensors. Polymers commonly explored in sensor research include PANi, polythiophene (PT), poly(3,4-ethylenedioxythiophene) (PEDOT), and polypyrrol (PPy), sometimes with other constituents, to enhance their sensing capability. Some of these such as PANi (Norris et al. 2000 Zhu et al. 2006a) and PPy (Kang et al. 2005 Nair et al. 2005) (as well as their hlends), can be readily electrospun into nanofibers. Polyaniline is somewhat unique in that its doped state can be controlled by the pH of the medium, allowing it to exist either as the emaraldine base or as the salt (Scheme 8.1). Simple acids and... 

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