Polyaniline nanofibers

Figure 8.5 SEM image of (a) pristine carbon nanofibers, (b) carbon nanofiber/polyaniline before mixing with N-methyl-2-pyrroUdone (NMP) (c) SEM image, and (d) TEM image of carbon nanofiber/polyaniline after mixing with NMP. Reprinted with permission from [31] Copyright (2005) Elsevier.

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... 

Yan X, Tai Z, Chen J, Xue Q (2011) Fabrication of carbon nanofiber-polyaniline composite flexible paper for supercapadtor. Nanoscale 3 212-216... 

The polymer resulting from oxidation of 3,5-dimethyl aniline with palladium was also studied by transmission electron microscopy (Mallick et al. 2005). As it turned out, the polymer was formed in nanofibers. During oxidative polymerization, palladium ions were reduced and formed palladium metal. The generated metal was uniformly dispersed between the polymer nanofibers as nanoparticles of 2 mm size. So, Mallick et al. (2005) achieved a polymer- metal intimate composite material. This work should be juxtaposed to an observation by Newman and Blanchard (2006) that reaction between 4-aminophenol and hydrogen tetrachloroaurate leads to polyaniline (bearing hydroxyl groups) and metallic gold as nanoparticles. Such metal nanoparticles can well be of importance in the field of sensors, catalysis, and electronics with improved performance. 

Banerjee S, Kumar A (2010) Dielectric behavior and charge transport in polyaniline nanofiber reinforced PMMA composites. J Phys Chem Solids 71 381... 

Li D, Huang J, Kaner RB (2009) Polyaniline nanofibers a unique polymer nanostructure for versatile applications. Acc Chem Res 42 135... 

Observations The preparation of helical polyaniline nanofibers has been a 6-year... 

Polymer nanofiber networks consisting of achiral polyaniline were prepared by Epstein et al. (3) by oxidizing aniline with ammonium peroxydisulfate and then doping with methanesulfonic acid. 

S. Virji, J. X. Huang, R. B. Kaner, and B. H. Weiller, Polyaniline nanofiber gas sensors Examination of response mechanisms , Nano Letters... 

Among conductive plastics, polyaniline has attracted much interest because of its environmental stability and its tunable electrical properties. Composite materials consisting of polyaniline nanofibers... 

Zhou, Y. Freitag, M. Hone, J. Staii, C. Johnson, A. T. Pinto, N. J. MacDiarmid, A. G., Fabrication and electrical characterization of polyaniline-based nanofibers with diameter below 30nm, Appl. Phys. Lett. 2003, 83, 3800-3802... 

Sun QH et al (2009) Fabrication of aligned polyaniline nanofiber array via a facile wet chemical process. Macromol Rapid Commun 30(12) 1027-1032... 

Huang JX, Kaner RB (2004) A general chemical route to polyaniline nanofibers. J Am Chem Soc 126 851-855... 

Huang JX, Virji S, Weiller BH, Kaner RB (2003) Polyaniline nanofibers facile synthesis and chemical sensors. J Am Chem Soc 125 314-315... 

Nanofibers can also be deposited directly on device substrates. Polyaniline being soluble, the electrospinning process has been successfully utilized for the production of polyaniline nanofibers [48]. However, this process cannot be directly employed for producing PPy nanofiber due to the intractability of PPy. 

Studies performed by Yuan et al. on conductive polyaniline (PANI) nanofibers, P3DOT, and CNT thin films show that aU three are capable of forming highly compliant electrodes with fault tolerant behavior [225]. Nanowires and tubes are of particular interest since they are capable of maintaining a percolation network at large strains, thus reducing the required electrode thickness while still allowing for maximum strain performance. 

Lam T, Tran H, Yuan W, Yu Z, Ha SM, Kaner R, Pei Q (2008) Polyaniline nanofibers as a novel electrode material for fault-tolerant dielectric elastomer actuators. Proc SPIE 6927 692700... 

Figure 2.8 Snapshots showing interfacial polymerization of aniline in a water/chloroform system. From (a) to (e), the reaction times are 0, 1.5, 2.5, 4, and 10 min, respectively. The top layer is an aqueous solution of 1.0 M HCIO4 and APS the bottom layer is aniline dissolved in chloroform. (Reprinted with permission from Journal of the American Chemical Society, A General Chemical Route to Polyaniline Nanofibers by J. Huang and R. B. Kaner, 126, 3, 851-855. Copyright (2004) American Chemical Society)...

Figure 2.10 Schematic representation of the growth and elongation of an initially formed nanofiber in a dilute solution. (Reprinted with permission from Synthetic Metals, A Simple Approach to Control the Growth of Polyaniline Nanofibers by N.-R. Chiou and A. J. Epstein, 153, 69-72. Copyright (2005) Elsevier Ltd)...

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)...

Figure 2.33 PANI-NFs/Au nanoparticle bistable digital memory device (from Table of Contents of Reference 504). (Reprinted with permission from Nano Letters, Polyaniline nanofiber/Gold Nanoparticle Nonvolatile Memory by R. j. Tseng, J. Huang, j. Ouyang et ai, 5, 6, 1077-1080. Copyright (2005) American Chemical Society)...

N. J. Pinto, A. T. Johnson, Jr., A. G. MacDiarmid, C. H. MueUer, N. Theofylaktos, D. C. Robinson, and F. A. Miranda, Electrospun polyaniline/polyethylene oxide nanofiber field-effect transistor, Appl. Phys. Lett., 83, 4244—4246 (2003). 

X. Zhang and S. K. Manohar, Polyaniline nanofibers chemical synthesis using surfactants, Chem. Commun., 2360-2361 (2004). 

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