Fluorescence Studies of Pyrene-Labeled Polymeric Surfactants

摘要

The synthesis of a fluorescently labeled water-soluble terpolymer based onacrylamide (AM) and the surface-active monomer sodium 11-Acrylamidoundecanoate (SA) is reported. Incorporation of 2-(1-pyrenylsulfonamido) ethyl acrylamide (APS) into the monomer feed yields a terpolymer with solution properties that are different from previously synthesized AM/SA copolymers. APS fluorescent label acts as a model hydrophobe; changes in pH and ionic strength that drive the viscosity response in AM/SA copolymers also affect the fluorescence emission properties of the APS label. Steady-state fluorescence emission studies reveal significant constriction of the polymer chain as pH decreases or electrolyte concentration increases. Fluorescence quenching studies suggest that the salt-induced chain collapse results in enhanced structuring of mixed aggregates formed by SA and APS units. Highly sensitive photophysical techniques confirm the pronounced pH and salt-responsiveness of AM/SA-based polymers observed in viscosity studies. jg p.2.