Star-Brush-Shaped Macromolecules: Peculiar Properties in Dilute Solution

Star-brush-shaped poly(ε-caprolactone)-block-poly(oligo(ethylene glycol) methacrylate (PCL-b-POEGMA) macromolecules were synthesized and studied by molecular hydrodynamic methods. The values of the intrinsic viscosity, the velocity sedimentation coefficient, the translational diffusion coefficient, and the frictional ratio were obtained in acetone. Molar masses (M) were determined by the Svedberg relation, and the correlations between the hydrodynamic values and the molar mass were obtained in the range of 19 < M × 10–3 g mol–1 < 124. Comparison of the scaling indexes of the intrinsic viscosity and sedimentation velocity coefficient versus molar mass corresponding to the conventional four-arm stars macromolecules with that of the star-brush-shaped copolymer macromolecules shows that the star-brush-shaped PCL-b-POEGMA macromolecules have the more dense organization in space which is connected with their different topology in contrast to the conventional stars macromolecules. The model of the PCL-b-POEGMA macromolecules based on the ensemble of their hydrodynamic characteristics is discussed.