Interaction between oxidized polyaniline and oppositely charged amphiphilic assemblies in an aqueous/organic biphasic...

Amphiphilic assemblies (AAs) are known to interact with polyelectrolytes in such a manner that the dynamic AAs retain their structural features, but the polyelectrolytes undergo conformational changes. This article reports that a charge bearing, rigid, water insoluble and oxidized conjugated polymer, polyaniline, can withstand such conformational changes and at the same time force the AAs to disassemble. An interfacial setup, comprising of an aqueous/organic interface, was utilized to study the disassembly process and the subsequent phase transfer phenomenon of the in situ synthesized polymer. It has further been demonstrated that the phase transfer occurred only when the concentration of the amphiphile was at and above its critical aggregation concentration. Moreover, fine dispersions of polyaniline were obtained initially in the aqueous phase and later in the organic phase. These fine dispersions suggest possibilities for better processing of this otherwise "difficult to process" polymer. The disassembly phenomenon was followed by changes in fluorescence emission and UV-vis absorption spectra of an entrapped probe molecule, recorded before and after the interaction. Changes in particle size upon disassembly were studied by dynamic light scattering. Dispersions of the polymer in the two phases were realized from transmission electron micrographs and UV-vis absorption spectra of the dispersed polymer.