Polyanilines sulfonated

Massoumi and Entezami [92] reported the controlled release of dexamethasone sodium phosphate (DMP) from a conducting polymer bilayer film consisting of a PPy inner film doped with DMP and poly(N-methylpyrrole)/polystyrene sulfonate (PNMP/PSS) or polyaniline sulfonate (SPANI) outer film. DMP was released from the inner film by an application of less than —0.6 V. In this device, the outer polymer layer functions as an ion and solvent barrier and also effectively reduces the rate of DMP release under an applied reducing electrochemical field, thereby providing an additional route to controlling release rates. 

In self-doped polyaniline, sulfonic groups induce changes in the geometry of the polyaniline backbone [152], affecting the physicochemical properties of the polymer. Comparative electronic absorption... 

A. Kitani, K. Satoguchi, K. Iwai, S. Ito, Electrochemical behaviors of poly-aniline/polyaniline-sulfonic acid composites, Synthetic Metals 1999, 102, 1171. 

Barra, G.M.O., Jacques, L.B., Orefice, R. L and Carneiro, J.R.G. (2004) Processing, characterization and properties of conducting polyaniline-sulfonated SEBS block copolymers. Eur. Polym.J., 40, 2017-2023. 

Polyaniline-sulfonic diphenyl amine Structure, electrical conductivity [106]... 

Polyaniline (PANI) can be formed by electrochemical oxidation of aniline in aqueous acid, or by polymerization of aniline using an aqueous solution of ammonium thiosulfate and hydrochloric acid. This polymer is finding increasing use as a "transparent electrode" in semiconducting devices. To improve processibiHty, a large number of substituted polyanilines have been prepared. The sulfonated form of PANI is water soluble, and can be prepared by treatment of PANI with fuming sulfuric acid (31). A variety of other soluble substituted AJ-alkylsulfonic acid self-doped derivatives have been synthesized that possess moderate conductivity and allow facile preparation of spincoated thin films (32). 

Fig. 1. (a) Comparison of normalised electrical conductivity of individual MWCNTs (Langer 96 [17], Ebbesen [18]) and bundles of MWCNTs (Langer 94 [19], Song [20]). (b) Temperature dependence of resistivity of different forms (ropes and mats) of SWCNTs [21], and chemically doped conducting polymers, PAc (FeClj-doped polyacetylene [22]) and PAni (camphor sulfonic acid-doped polyaniline [2. ]) [24]. 

PP-g-MA) silicate nanocomposites and intercalated thermoset silicate nanocomposites for flame-retardant applications were characterised by XRD and TEM [333], XRD, TEM and FTIR were also used in the study of ID CdS nanoparticle-poly(vinyl acetate) nanorod composites prepared by hydrothermal polymerisation and simultaneous sulfidation [334], The CdS nanoparticles were well dispersed in the polymer nanorods. The intercalation of polyaniline (PANI)-DDBSA (dodecylbenzene-sulfonate) into the galleries of organo-montmorillonite (MMT) was confirmed by XRD, and significantly large 4-spacing expansions (13.3-29.6A) were observed for the nanocomposites [335],... 

Narasimhan, M. Hagler, M. Cammarata, V. Thakur, M. 1998. Junction devices based on sulfonated polyaniline. Appl. Phys. Lett. 72 1063-1065. 

Note 4 A polymer that shows electric conductivity due to the transport of ionic species is called an ion-conducting polymer an example is sulfonated polyaniline. When the transported ionic species is a proton as, e.g., in the case of fuel cells, it is called a protonconducting polymer. 

LB films prepared from poly-thiophene-3-acetic acid stearylamine or sulfonated polyaniline stearylamine polyion complexes, transferred to substrates, and doped by SbCls Absorption and infrared spectra, X-ray diffraction, and conductivity measurements Lateral d.c. conductivities of doped films were moisture dependent and were as high as 2 S cm"molecular organization consisted of randomly oriented polymers lying as extended chains parallel between the substrates and sandwiched between layers of stearylamine molecules whose chains were interdigitated 772... 

AlvaK, Kumar J, Marx KA et al (1997) Enzymatic synthesis and characterization of a novel water soluble polyaniline poly(2, 5 diamino benzene sulfonic acid). Macromolecules 30 4024-4029... 

Sakharov IY, Vorobiev AC, Leon JJC (2003) Synthesis of polyelectrolyte complexes of polyaniline and sulfonated polystyrene by palm tree peroxidase. Enzyme Microb Technol 33 661-667... 

Nevertheless, there are cases in which conductivity is not governed by disorder, or at least in a less drastic way. This is the case of highly conducting polyacetylene [27]. Conductivity approaching the value of copper at room temperature has been reported, and a high value is still observed at low temperature. Recently, polyaniline with camphor sulfonic add (CSA) as the counterion has been reported to present an almost flat temperature dependence of conductivity [28]. Such examples are quite rare, but they are of major importance for an understanding of the intrinsic conduction process. 

The synthesis of self-doped conducting polyaniline was achieved by sulfonation of the aromatic units with fuming sulfuric acid. The sulfonated polyaniline has a conductivity of 0.1 S/cm, which is independent of pH [191]. 

Figures Schematic illustrations of (a) 50% sulfonated and (b) 100% sulfonated polyanilines (self-doped forms).

Hydrochloric acid as well as camphor sulfonic acid doped polyaniline prepared in chloroform often have [59] log a proportional to T as expected for quasi-one-dimensional variable range hopping, Equations (3) and (4). Generally, the higher conductivity samples have a weaker temperature dependence at low temperatures (Tq 700-1000 K for T<80 K), and lower conductivity samples a stronger temperature dependence (To 4000 K). The smaller Tq for the more highly conducting samples has been associated with weaker localization due to improved intrachain and interchain order. 

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