Complex Formation of Polyacrylic Acid with Surfactants of Different Hydrophobicity

Abstract

Complex formation processes of polyelectrolytes with surfactant ions are close model to protein - lipid interactions in living organisms. Furthermore, polymer – surfactant complexes are widely used as stabilizers of industrial dispersions and structurants of soil. When using the polymer-surfactant complexes the hydrophilic-lipophilic balance has the great importance. The interaction of polyacrylic acid with alkylammonium salts of different hydrophobicity: cetyltrimethylammonium bromide, dilaurildimethylammonium bromide and dioctadecyldimethylammonium chloride was studied by potentiometry, spectrophotometry, viscometry and electrophoresis methods. It was established that the complex formation of polyacrylic acid with cationic surfactants is carried out due to the electrostatic interaction between carboxyl groups of the polymer and cations of surfactants, which stabilized by hydrophobic interactions between their non-polar parts. The phenomenon of hysteresis in the change of the reduced viscosity of system surfactant /polyacrylic acid with temperature variation in the range of 20-60 °C was found. The possibility of using the complex formation process for water purification from CTAB has been shown. The degree of purification is 99.6-99.8%.