Poly 2-methoxyaniline-5-sulfonic acid conductivity

The converse approach to inducing chirality into conducting polymer chains, namely, the incorporation of an optically active cation, has also been successfully employed in our laboratories to produce the first optically active water-soluble sul-fonated PAn. Poly(2-methoxyaniline-5-sulfonic acid) has been prepared in optically active form through the electropolymerization of 2-methoxyaniline-5-sulfonic acid in the presence of (/ )-(+)- or (.S )-(-)-l-phenylethylamine.29 The optical activity and electroactivity of the chiral sulfonated PAn s are retained when immobilized on poly(4-vinylpyridine) (see Chapter 5). 

The related fully sulfonated, self-doped polymer poly(2-methoxyaniline-5-sulfonic acid) (PMAS 9) may be prepared under normal atmospheric pressure by the oxidation of 2-methoxyaniline-5-sulfonic acid (MAS) monomer with aqueous (NH4)2S208 in the presence of ammonia or pyridine (to permit dissolution of the MAS monomer).141 The polymerization pH was therefore >3.5. Subsequent studies showed that the product consisted of two fractions a major fraction with Mw of ca. 10,000 Da whose electrical conductivity and spectroscopic and redox switching properties were consistent with a PAn emeraldine salt, as well as a nonconducting, electroinactive oligomer (Mw ca. 2,000 Da).143 144 Pure samples of each of these materials can be obtained using cross-flow dialysis.145... 

De Paoli and coworkers7 have used the more soluble poly(o-methoxyaniline) doped with p-toluene sulfonic acid to prepare a composite blend with poly(epichlorohydrin-co-ethylene oxide), but conductivities were relatively low (10-3 S cm-1) even with a high 50% (w/w) conducting polymer loading. 

Conducting polymers may contain functional groups appended to the polymer backbone, as in the case of poly(2-methoxyaniline-5-sulfonic acid) [72] or poly((4-(3-pyrrolyl))butane sulfonate) [73], and such groups may interact with metal interfaces. Indeed, metal salts were found to cause conformational... 

Unlike ring sulfonated polyaniline, the fully sulfonated, water-soluble, polyaniline, poly(2-methoxyaniline-5-sulfonic acid), is shown to be remarkably inert to alkaline dedoping and remains in the conducting emeraldine salt form even in 2.0 M NaOFi [164], The UV-Vis near-infrared spectra of poly(2-methoxyaniline-5-sulfonic acid) solution as a function of plT are shown in Figure 2.28. In water, the absence of a localized polaron band in the range of 750-900 run and presence of a broad absorption in NIR suggests an extended coil conformation... 

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