Diffusion and Scaling Behavior of Polymer-Surfactant Aggregates

The self-diffusion coefficient of poly(ethyleneoxide) (PEO) in self-assembled aggregates of PEO and sodium dodecyl sulfate (SDS) in water at PEO concentrations well below the overlap point has been determined by pulse gradient spin echo NMR spectroscopy. The results show that individual polymer coils undergo significant expansion upon complexation with the surfactant. The diffusion coefficients of PEO coils saturated with SDS scale with molecular weight of the polymer as D~M^νₐₚₚ with νₐₚₚ0ex0ex=0ex0ex0.60±0.02. The value of νₐₚₚ in this case is different from νₐₚₚ0ex0ex=0ex0ex0.55±0.01 for the surfactant free coil.