Controlled Stability of a Polymer-Colloid Complex in Aqueous-Saline Solutions

The interaction of a labeled polymethacrylate anion with aliphatic and aromatic cationic surfactants of various structures in aqueous and aqueous-saline solutions has been studied by fluorescent methods. It has been shown that variations in the pH of solution, the concentration of surfactants, the number of methylene groups in an alkyl fragment, and the nature of an amino group may efficiently affect the binding of surfactants by polyanion molecules. A successive and noticeable increase in the stability of complexes after replacement of the tertiary groups of a surfactant with tertiary, secondary, or primary amino groups indicates the significance of the steric fit of charges in ion pairs. This effect may be especially important for designing polymer-colloid systems with controlled stability in aqueous-saline solutions.