Contractive Polymeric Complex Micelles as Thermo‐Sensitive Nanopumps

Complex micelles were obtained from PS‐ b ‐PNIPAM‐ b ‐PAA micelles and PEG‐ b ‐P4VP block copolymers via the strong electrostatic interaction and hydrogen bonding between PAA and P4VP blocks in water. The PS block formed the core and the PAA/P4VP complex shell functioned as a semi‐permeable membrane which could control the permeation of small molecules. Between the core and shell, the large fluid‐filled space that was formed with the thermoresponsive PNIPAM gel could retain the loaded drug for a long period of time. With increasing temperature, the shrinkage of the PNIPAM coils pumped the drug out of the complex micelles. The complex micelles functioned as a contractive “nanopump”, which could potentially be applied as a thermosensitive controlled release system.