Temperature-responsive multilayered micelles formed from the complexation of PNIPAM-b-P4VP block-copolymer and PS-b-PAA core–shell micelles

Multilayered micelles with a polystyrene (PS) core, a swollen poly(acrylic acid) (PAA)/poly(4-vinyl pyridine) (P4VP) complex shell and a poly(4-vinyl pyridine)-block-poly(isopropyl acryl amide) (P4VP-b-PNIPAM) block-copolymer corona was synthesized by complexation between PNIPAM₅₃-b-P4VP₁₀₉ block-copolymers and the PS₁₂₀-b-PAA₄₇ diblock-copolymer core–shell micelles in ethanol due to the hydrogen bonding between the AA units and 4VP units. The surface of the micelle has been modified and a temperature sensitive block PNIPAM was introduced into the corona of the micelles. After being dialyzed against acidic water, PNIPAM corona would collapse onto the PAA/P4VP shell and the excessive P4VP shell would extend into the acidic solution to form the corona reversed micelles when the micelle aqueous solution was heated to 45 °C. The whole process was performed using dynamic light scattering (DLS), static light scattering (SLS), atom force microscope (AFM) and nuclear magnetic resonance (NMR).