Effects of various factors on the interfacial mass transfer phenomenon and dispersion of polyaniline in an aqueous/organic bi-/tri-phasic system

Upon electrostatic interaction between positive charge-bearing oxidized polyaniline and negatively charged amphiphile molecules (AMs), the AMs get attached onto the polymer chains, resulting in charge neutralization and formation of hydrophobic cover on the polymer surface. In an interfacial polymerization setup, comprising of an aqueous/organic interface, this attachment phenomenon essentially leads to aqueous-to-organic phase transfer of the in situ synthesized polymer. As a result, the initial fine dispersion of polyaniline obtained in the aqueous phase gets converted to a fine dispersion in the organic phase. These fine dispersions in either phase shall render the possibility of better solution processing ability of this otherwise 'difficult-to-process' polymer. Herein, we demonstrate how factors like temperature, rate and extent of agitation, concentration of AMs, nature and number of organic phases, phase composition, natural interfacial presence of AMs, and gravity affect the extent of phase transfer. While, both the extent of transfer and the time required for achieving the maximum transfer depended on the concentration of AMs below its critical aggregation concentration, only the latter was found to vary with the rate of stirring. Presence of interfacial AMs, gravity, and the number and nature of the organic phases were all found to affect the transfer process.