Ionomer-surfactant self-assembly in low-polarity solvents

A systematic study of complexation reactions of sulfonated polystyrene ionomers containing up to 5 molar percent of polar chain units with various oil-soluble surfactants is carried out in low-polarity organic solvents. Dipole-dipole attractions of the components lead to the formation of complexes characterized by limiting compositions and an unusual polymer-colloidal morphology of joint clusters and/or micelles. The limiting compositions (phi) for the complexes formed between ionomers and surfactant of the same charge (bis(2-ethylhexyl)sulfosuccinate sodium salt), or nonionic surfactants (primarily aliphatic amines) are equal to 15-30 surfactant molecules per one ionomer salt/acid group on average, with phi depending on the hydrophilic-lypophilic balance of the components, the initial aggregation state of surfactant and the nature of low-polarity solvent. Ionomer-surfactant complexation is accompanied by disruption of self-contacts of ionomer salt/acid groups, leading to ''unfastening'' and expansion of the ionomer coils in dilute solution. The ''driving force'' of the ionomer-surfactant complexation and the structure of the resultant complexes are discussed.