A Fluorescence Probe Study of Low Molecular Weight Poly(Methallyl Sulfonate-Vinyl Acetate) Copolymers

When vinyl acetate is copolymerized with sodium methallyl sulfonate, low molecular weight polymers are produced. By controlling the starting mixture composition, the negatively charged monomer content of the polymer chain was varied between 2.5 and 10%. The effect of these copolymers on the fluorescence properties and quenching of pyrene was investigated. It was found that fluorescence intensity and lifetimes increase when the polymer concentration increases. Quenching by nitro-methane, Cu(II) ions, and oxygen was greatly reduced compared to quenching in water. The effect is more pronounced for the copolymers with a lower charge content. The results can be interpreted by an aggregation of the polymer chains. These aggregates provide sites for the pyrene molecules, where the radiationless decay processes are reduced, and they are also protected from impurity quenching.