Light-switchable vesicles from liquid-crystalline homopolymer-surfactant complexes.

Polymer vesicles, or polymersomes, attract increasingly growing interest due to the various applications ranging from cosmetics to drug delivery. At DWI a novel concept of polymersome fabrication based on non-stoichiometric complexation of a polybase with an amphiphilic ligand bearing a sulfonic acid group has been developed. The structure of the complex in the vesicles was found to be similar to that in the bulk, where polymer backbones are sandwiched between the bilayers formed by the ligand molecules. In contrast to conventional polymersomes formed by block-copolymers, the polymer backbones in the vesicle walls are largely parallel to the surface. This can contribute to their high mechanical stability. The large amount of remaining free binding sites in this system makes it possible to additionally incorporate different functional molecules into the vesicles. Furthermore, the collapse of the polymersome can be induced by UV-irradiation due to the trans-to-cis transition of the azo-groups, which leads to the isotropization of the layered structure. This feature could make this system promising for the controlled delivery applications.