(722v) Physical Chemical Properties of Phase Separated Polymersomes

Polymersomes made of neutral poly(ethylene oxide)-polybutadiene (PEO-PBD) and negatively charged poly(acrylic acid)-polybutadiene (PAA-PBD) diblock copolymers can laterally segregate into coexisting domains in a certain pH range by calcium cross-bridging between PAA-PBD chains. The phase diagram for phase separation reveals that domain formation occurs in a surprisingly small region of pH and calcium concentration. The sensitivity of these domains to solution conditions after their formation was investigated by varying pH and calcium concentration. 3D images of polymersomes were recorded via confocal fluorescence microcopy imaging, which allowed to obtain domain area fractions using a 2D mapping algorithm. We furthermore studied the effect of temperature on polymersome phase separation as well as the mechanical properties of pure PAA-PBD polymersomes.