PHOTOPHYSICAL STUDIES OF HYDROPHOBICALLY FUNCTIONALIZED POLYIONENE SYSTEMS IN AQUEOUS-SOLUTIONS

Complexes of polyionene and anionic dyes and surfactant were prepared by exchange reaction of counterions in the parent polymer. Fluorescenc e studies were conducted to observe some characteristic behaviour of t hese complexes in water. Polyionenes with aromatic hydrocarbons adopt an open conformation and there is no evidence for interpolymer interac tions. On the contrary, polyionenes with long aliphatic counterions ea sily form microdomains in aqueous solution due to hydrophobic interact ion as evidenced by an increase in excimer emission. Microdomains have an interpolymer nature, as confirmed by measurements of energy transf er from naphthalene to pyrene moieties. Polyionenes with SDS counterio ns interact with external surfactant molecules and form polymer-surfac tant aggregates. Electrostatic repulsions between aggregates dominate on hydrophobic interaction between polymer chains and are responsible for conformational changes.