Title

Water-Soluble Copolymers .40. Photophysical Studies of the Solution Behavior of Associative Pyrenesulfonamide-Labeled Polyacrylamides

Document Type

Article

Publication Date

3-30-1992

Department

Polymers and High Performance Materials

Abstract

Photophysical studies were conducted on copolymers of acrylamide containing less than 0.5 mol % N-[(1-pyrenylsulfonamido)ethyl]acrylamide in order to relate the aqueous solution behavior to the molecular structure. The copolymer prepared via a surfactant technique was shown to possess some inherent blockiness or short runs of the pyrenesulfonamide label in dilute solution. Intermolecular associations were observed above a critical concentration of polymer. I(e)/I(m) values from steady-state fluorescence paralleled the rheological response as a function of concentration. The copolymer prepared by solution polymerization showed random incorporation of the pyrenesulfonamide comonomer and no intermolecular association tendency over the concentration range studied. The pyrenesulfonamide labels were shown to form ground-state aggregates within relatively accessible hydrophilic environments in both polymers. Associative thickening behavior observed in the surfactant-polymerized copolymer is consistent with microphase organization of hydrophobic pyrenesulfonamide aggregates above a critical concentration. Fluorescence quenching has been used to probe the microenvironment around the label.

Publication Title

Macromolecules

Volume

25

Issue

7

First Page

1887

Last Page

1895