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Polyaniline, sulfonic acid derivatives

A number of water-soluble polyaniline derivatives have been developed in recent years. Incorporation of sulfonate groups onto the polymer backbone imparts water solubility to the polymer. In one process, this is accomplished by treating the polymer with fuming sulfuric acid which results in a sulfonic acid ring-substituted derivative that is alkali soluble but only upon conversion to the nonconducting sulfonate salt form. [Pg.574]

Polyaniline and its substituted derivatives, such as poly(o-toluidine), poly(o-anisidine), poly(N-methylaniline), poly(N-ethylaniline), poly(2,3-dimethylaniline), poly(2,5-dimethylaniline) and poly (diphenylamine) have been reported [36] to show measurable responses (sensitivity 60%) for short chain alcohols (viz., methanol, ethanol and propanol) at concentrations up to 3000 ppm. The change (decrease) in resistance of the polymers on exposure to alcohol vapors has been explained based on the vapor-induced change in the crystallinity of the polymer. Polypyrrole (PPy) incorporated with dodecyl benzene sulfonic acid and ammonium persulfate has been reported to show a linear change in resistance when exposed to methanol vapor in the range 87-5000 ppm [37]. The response is rapid and reversible at room temperature. [Pg.581]

Using functional molecules as structural directors in the chemical polymerization bath can also produce polyaniline nanostructures. Such structural directors include surfactants [16-18], liquid crystals [19], polyelectrolytes (including DNA) [20,21], or complex bulky dopants [22-24]. It is believed that functional molecules can promote the formation of nanostructured soft condensed phase materials (e.g., micelles and emulsions) that can serve as soft templates for aniline polymerization (Figure 7.3). Polyelectrolytes such as polyacrylic acid, polystyrenesulfonic acid, and DNA can bind aniline monomer molecules, which can be polymerized in situ forming polyaniline nanowires along the polyelectrolyte molecules. Compared to templated syntheses, self-assembly routes are more scalable but they rely on the structural director molecules. It is also difficult to make nanostructures with small diameters (e.g., <50 nm). For example, in the dopant induced self-assembly route, very complex dopants with bulky side groups are needed to obtain nanotubes with diameters smaller than 100 nm, such as sulfonated naphthalene derivatives [23-25], fidlerenes [26], or dendrimers [27,28]. [Pg.213]

C. H. Yang, T. C. Wen, Polyaniline derivative with external and internal doping via electrochemical copolymerization of aniline and 2,5-diaminobenzene-sulfonic acid on Ir02-coated titanium electrode, of the Electrochemical Society 1994,141, 2624. [Pg.147]

In addition to functionalization of polyanilines with sulfonic and carboxylic acids, the corresponding phosphonic acid derivatives have been prepared, o-Aminobenzylphosphonic acid was prepared as shown in Figure 20.54 [42,43]. Oxidative coupling of the above monomer in an acidic medium yielded poly(o-aminobenzylphosphonic acid) (Figure 20.55). Spectroscopic analysis was consistent with head-to-tail oxidative coupling through the /Jara-position. The as-prepared polymer was in its emeraldine oxidation state in which 43% of the N-atoms were protonated by the pendent acid. This polymer was insoluble in both non-aqueous solvents and aqueous acidic solutions. [Pg.853]

The IBM group led by Brusic et al. [57,58] also studied the use of polyaniline derivatives for corrosion protection of copper as well as silver. The unsubstituted polyaniline, in neutral base form, provided good corrosion protection both at open-circuit potential and at high anodic potentials. The dissolution of metal (both Cu and Ag) was decreased by a factor of 100 when the metal surface was completely covered by the neutral polyaniline. However, polyaniline doped with dodecylbenzene-sulfonic acid (the conductive form of the polymer) increased the corrosion rate of Cu and Ag in water. The doped polymer in contact with the metal is spontaneously reduced at a rate faster than the oxygen reduction rate. The faster cathodic process in turn increases the overall rate of the anodic reaction, which is the dissolution of Cu and Ag, as opposed to the formation of a passive oxide layer. [Pg.913]

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). [Pg.242]

A second method of introducing sulfonate groups is accomplished by deprotonating polyaniline base and reacting with a sultone, i.e., 1,3-propanesultone [22]. This gives rise to an N-substituted polyaniline derivative that is water soluble. Another route involves the polymerization of sulfonated aniline monomer such as sodium salt of diphenylaminesulfonic acid [23]. [Pg.574]

Aside from considerations of the polymer form itself, polyaniline can be doped and derivatized in a variety of ways. First, polyaniline can be polymerized in the presence of a variety of acids, which critically influences the resulting electronic properties [1-15]. The particular acid used and polymerization process employed can affect the degree of crystallinity observed [10-15,17-29]. Multiple dopants and substitutions have been achieved in the hope of increasing both the conductivity and solubility of these materials. The derivatives are simple polyanilines functionalized with complex ions such as aryl-SOj, camphorsulfonates, and perfluoroalkyl (and aryl) sulfonates. Dopants vary from simple anions, to oxyanions, to the more typical iodide ions [10-15,17-29,38-44]. The functionalization and/or doping affects, the band population, and the polyaniline chain conformation in turn influence the resulting electronic and structural properties of the polymer. [Pg.2]


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Conductivity polyaniline sulfonic acid derivative

Polyaniline derivatives

Polyaniline sulfonated derivatives

Polyaniline sulfonation

Polyaniline, sulfonic acid derivatives solubility

Polyanilines sulfonated

Sulfone derivative

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