Macromolecular aggregation of aqueous polyacrylic acid in the presence of surfactants revealed by resonance Rayleigh scattering

On the basis of the relationship between macromolecular aggregate and resonance Rayleigh scattering (RRS) intensity, RRS spectra were utilized to monitor macromolecular aggregating process in poly(acrylic acid) (PAA). No probe and labeling were incorporated; RRS can reveal the macromolecule extension or contraction under external stimuli such as the changes in pH and ionic strength, as well as the addition of surfactant. Results indicated that the, addition of base, acid and NaCl altered macromolecular phase behavior of PAA in aqueous solution due to electrostatic effect. Besides, sodium dodecyl sulfate (SDS) or cetyltrimethylammonium bromide (CTAB) interacted with PAA in Solution to form polymer-surfactants complexes, inducing macromolecular chain aggregate. On the basis of the analysis of the results, two models were proposed in this work to explain the observed phenomena. RRS is a sensitive method to characterize the macromolecular aggregate.