Amphiphilic star-shaped brushes based on block copolymers-molecular micelles for the delivery of drugs: Hydrodynamic studies

Brush-shaped molecular stars of poly(ɛ-caprolactone)-block-poly(oligo(ethylene glycol) methacrylate) are synthesized, their hydrodynamic properties are studied, and their molecular characteristics are measured. For dilute solutions of the copolymers in acetone, viscous flow, velocity sedimentation, and translational diffusion of the macromolecules are investigated. The molecular masses of the copolymers are determined via the Svedberg relation. Correlations between hydrodynamic characteristics and molecular masses in the range 46 < M × 10−3 g mol−1 < 266 are obtained. The existence of scaling relationships makes it possible to infer that the resulting copolymers belong to a hydro-dynamically similar series of macromolecules: hydrodynamic homologs. It is shown that copolymer macromolecules have a denser organization in space than that of both linear macromolecules and conventional molecular stars. A model of macromolecules of poly(ɛ-caprolactone)-block-poly(oligo(ethylene glycol) methacrylate) copolymers that is based on their hydrodynamic characteristics is discussed.