Self-Assembly of Giant Polymer Vesicles by Light-Assisted Solid Hydration

An amphiphilic copolymer containing a terminal spiropyran (P-SP) forms giant polymer vesicles when exposed to ultraviolet (UV) light. The process involves photoisomerization of the spiropyran to the corresponding hydrophilic merocyanine isomer, which significantly improves the efficiency of film hydration and facilitates the self-assembly of the polymer in water. Giant vesicles formed by light-assisted hydration have diameters ranging from 5 to 25 micrometers, and can be observed and quantified by confocal fluorescence microscopy. Rapid and efficient formation of giant vesicles only occur during exposure of P-SP to UV light and within the area delimited by the light beam. Light-assisted hydration offers high spatial and temporal control over vesicle formation, conditions not easily fulfilled by other techniques.