Poly 2-methoxyaniline

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). 

A wide range of alkyl- and alkoxy-substituted PAn s of the general types 6 and 7 have been synthesized by the chemical or electrochemical oxidation of appropriately substituted aniline monomers.133 Such substitution imparts markedly improved solubility in organic solvents to the emeraldine salt products compared to the parent (unsubstituted) PAn/HA salts. The poly(2-methoxyaniline) (POMA) species, in particular, has been the subject of extensive studies.134 137 This species has the additional attractive feature of being soluble in water after being wet with acetone. 

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... 

A composite actuator was constructed using a copolymer of PPy and poly(methoxyaniline) formed in p-phenol sulfonic acid (PPS). Higher actuation deformations were seen at low pH. Pure PPy(PPS) initially showed mixed cation and anion actuation when tested in 1 M NaCl, but the cathodic expansion was removed by the inclusion of 30% poly(methoxyani-line) and the extent of electrochemical creep was also diminished [144]. The inclusion of poly(2-methoxyaniline-5-sulfonate) (PMAS) into PPy(DBS) films improved the cathodic expansion of the films. The presence of the PMAS also led to some anodic film expansion in some electrolytes (e.g. KCl), but exclusively enhanced cation expansion in other electrolytes (TBAPF4) [145]. 

A. Tanaka, W. Takashima, and K. Kaneto, Improved cathodic expansions of polypyrrole films by poly(2-methoxyaniline-5-sulfonate) incorporation. Thin Solid Films, 499 (1-2), 179-184 (2006). 

FIGURE 11.11 Structure of poly(2-methoxyaniline 5-sulfonic acid). 

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... 

Figure 2.9 Structure of poly(2-methoxyaniline-5-sulfonic acid). (Reprinted from Synthetic Metals, 85, S. Shimizu, T. Saitoh, M. Uzawa, M. Yuasa, K. Yano, T. Maruyama, K. Watanabe, 1337. Copyright (1997), with permission from Elsevier.)...

Kane-Maguire and Wallace et al. [122] were first to report on self-doped, optically active poly(2-methoxyaniline-5-sulfonic acid). They electropolymerized 2-methoxyaniline-5-sulfonic acid in the presence of R)- +)- or (S)-(—)-l-phenylethylamine. The poly(2-methoxyaniline-5-sulfonic acid) films formed using enantiomers of amines exhibit intense mirror image circular dichroism spectra (Figure 2.15) in the visible region. Wallace et al. suggest that the optical activity in poly(2-methoxyaniline-5-sulfonic acid) is probably due to electrostatic binding... 

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... 

D. Z. Zhou, P. C. Innis, G. G. Wallace, S. Shimizu, S. I. Maeda, Electrosynthesis and characterisation of poly(2-methoxyaniline-5-sulfonic acid) - effect of pH control, Synthetic Metals 2000,114, 287. 

PABS polyaminobenzene sulfonic acid SWCNT single-walled carbon nanotube PANI polyanUine CNT carbon nanotube PMAS poly(2-methoxyaniline-5-sulfonic acid) MWCNT multiwalled carbon nanotube PEDOT poly(3,4-ethyl-ene dioxythiophene) PSS polystyrene sulfonated acid TMA trimethylamine TEA triethylamine Source. Data from Kukkola et al. (2012), etc. 

Leclerc et al. [78] have made a comparative study of the electropolymerized POT with those of alkoxy-substituted polyanilines. While POT exhibits an absorption maximum (310 nm) blue-shifted from PANI (315 nm), poly(2-methoxyaniline) shows a slightly red-shifted absorption peak (325 nm). The redox potential of poly(2-methoxyaniline) (0.08 V) is lower than that of POT (0.20 V). The electronic effect of the methoxy substituent alone cannot explain these observations and therefore steric as well as electronic effects of the substituents must be taken into consideration. It has been found that POT is less planar than alkoxy substituted polyanilines. However, the alkoxy mono-substituted polyanilines exhibit lower conductivity than that of POT, since the selectivity of the head-to-tail couplings is reduced by the incorporation of a methoxy group. Nevertheless, more regular and processable materials have been obtained with poly(2,5 -dialkoxyanilines). 

A covalently attached acid moiety to the polyaniline backbone can dope itself without an external dopant. A self-doped conducting polyaniline bearing phos-phonic acid, poly(2-methoxyaniline-5-phosphonic acid) (PMAP) is designed and... 

Analogous electrochemical oxidation of the monomer, 2-methoxyaniline in the presence of (+)- and (-)-HCSA, has provided a similar route to optically active poly(2-methoxyaniline), POMA. HCSA, films. ... 

The related fully sulfonated polymer, poly(2-methoxyaniline-5-sulfonic acid) 9 (PMAS) can be prepared imder normal atmospheric pressure by the oxidation of 2-methoxyaniline-5-sulfonic acid with aqueous (NH4)2S20g in the presence of ammonia or pyridine (to assist dissolution of the substituted monomer). ... 

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