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Despite the significant interest in poly(sulfonic acids) as proton conductors and acid catalysts, their dissociation behavior is poorly studied. The influence of the polyelectrolyte effect on the dissociation of the strong poly(acid) is frequently neglected. Moreover, the decrease in distance between the sulfonic groups is thought to enhance the acid strength or charge carrier concentration. Using simple and reliable methods (pH measurements and potentiometric titration), it is demonstrated that a strong poly(sulfonic acid) such as poly(2-acrylamido-2-methyl-1-propanesulfonic acid) displays a “limited” (predicted by the Manning-Oosawa theory) degree of dissociation in a salt-free solution and “maximal” degree of dissociation equivalent to the monomer analog in the presence of NaCl excess.

Two techniques of manufacturing a nanocomposite based on a complex of polyaniline with polymer acid and graphene are proposed. The electric conductivity of thin nanocomposite layers is higher than that of a polymer complex of polyaniline and strongly depends on the degree of oxidation of graphene. An explanation of the effect is suggested that takes into account electron interactions between the graphene planes and polyaniline backbone, as well as the possibility of formation of hydrogen bonds between functional groups of semioxidized graphene and polyacid. The results of surface topography analysis for thin layers of polyaniline and nanocomposite agree well with the regularities of the structure of each layer that are due to the above interactions between graphene and the polymer complex.

Liquid-crystalline state of dyes can be easy distinguished from the crystalline one by the appearance of characteristic long-wavelength optical absorption, the so-called J-band. Similarly, long-wavelength absorption of polyaniline is assumed to be the signature of its J-like liquid-crystalline state. When water evaporates from polyaniline adsorbed on a glass support during polymerization, the long-wavelength maximum at about 800 nm disappears, and one at 570 nm appears, characteristic for highly crystalline and strongly oriented thin film. Reversible red shift of long-wavelength absorption upon water adsorption is a significant feature of these films. By analogy with dyes, it is attributed to water-promoted superficial formation of J-like mesophase. Such surprising properties of wet films as propagation of chemical reduction and enhanced exciton transport, reported by us recently, can also be considered as a signature of the J-like liquid-crystalline state of polyaniline.

The matrix polymerization of aniline in the presence of mixtures of rigid-chain and flexible-chain polymer sulfoacids was investigated in the work. The optical, electric, and spectroelectrochemical properties of the forming interpolymer complexes of polyaniline, as well as their morphology, were studied. The dominating influence of rigid-chain polyacid on the process of formation of the interpolymer complexes of polyaniline even in the case of application of the mixture with the prevailing content of the flexible-chain polyacid was detected. The nonadditive dependence character of the viscosity of the mixtures of polyacid solutions, the duration of the induction period of aniline polymerization, and the optical absorbance and conductivity of the obtained complexes of polyaniline relative to polyacid ratios in the mixture was shown. The presence of the intermolecular interaction in the mixtures of polymer sulfoacids was shown via viscometry method, which may be the reason for the nonadditivity of the observed phenomena.