Stable Water-soluble Polyion Complex Micelles Composed of Oppositely Charged Diblock Copolymers and Reinforced by Hydrophobic Interactions

Polyion complex (PIC) micelles having a hydrodynamic radius of approximately 20 nm were prepared in water by simply mixing a pair of double hydrophilic oppositely charged diblock copolymers composed of a first block containing pendant phosphobetaine groups and a second cationic or anionic styrene-based polyelectrolyte block. The PIC micelles were stable under high salt concentration because the formation of the PIC micelles was driven by both electrostatic and hydrophobic interactions.