Dynamics of a triblock copolymer in a selective solvent for the middle block investigated using pulsed field gradient NMR

The concentration dependence of the self-diffusivity of a hydrogenated poly styrene-block-polybutadiene-block-polystyrene triblock copolymer in an n-he ptane solution (c = 0.58-6.9 g/100 mt) was investigated using the pulsed fi eld gradient NMR at 20-35 degrees C. The solvent is a preferential solvent for the middle block. At low concentrations, micelle-like aggregates (flowe rs) are observed, With increasing concentration larger aggregates (animals) are formed. These aggregates show a tendency to anomalous diffusion: excha nge of micelles between the aggregated and the nonaggregated state as well as restricted diffusion. At the highest concentrations, individual diffusio n of insoluble domains (nodes) is observed, but no transient network behavi or. The width of the distribution of self-diffusivities corroborates the fi ndings. Our results are in agreement with light scattering results publishe d previously.