ABC Triblock Copolymer Vesicles with Mesh-Like Morphology

Polymer vesicles made from poly(isoprene-<i>b</i>-styrene-<i>b</i>-2-vinyl pyridine) (PI-<i>b</i>-PS-<i>b</i>-P2VP) triblock copolymer confined within the nanopores of an anodic aluminum oxide (AAO) membrane are studied. It was found that these vesicles have well-defined, nanoscopic size, and complex microphase-separated hydrophobic membranes, comprised of the PS and PI blocks, while the coronas are formed by the P2VP block. Vesicle formation was tracked using both transmission and scanning electron microscopy. A mesh-like morphology formed in the membrane at a well-defined composition of the three blocks that can be tuned by changing the copolymer composition. The nanoscale confinement, copolymer composition, and subtle molecular interactions contribute to the generation of these vesicles with such unusual morphologies.