Polymerized ABA triblock copolymer vesicles

The synthesis and the characterization of a poly(2-methyloxazoline)-block-p oly(dimethylsiloxane)-block-poly(2-methyloxazoline) (PMOXA-PDMS-PMOXA) trib lock copolymer carrying polymerizable groups at both chain ends are describ ed. This copolymer forms vesicular structures in dilute aqueous solution, t he size of which can be controlled in the range from 50 nm up to about 500 nm. The methacrylate end groups of the triblock copolymer can be polymerize d in the vesicular aggregates using an UV-induced free radical polymerizati on. Static and dynamic light scattering, scanning electron microscopy, and transmission electron microscopy on both the resulting nanocapsules and the ir nonpolymerized precursors clearly show that the cross-linking polymeriza tion does not lead to morphological changes in the underlying vesicles. Mor eover, due to their cross-linked structure, the nanocapsules are shape pers istent, thus maintaining their integrity even after their isolation from th e aqueous solution.