Molecular exchange through membranes of poly(2-vinylpyridine-block-ethylene oxide) vesicles.

The molecular exchange of tracer molecules through the membranes of dispersed vesicles of the block copolymer poly(2-vinylpyridine-block-ethylene oxide) was studied by using NMR spectroscopy combined with pulsed field gradients. The hydrodynamic radius of the tracer molecules was varied systematically to obtain a permeability profile of the vesicle membrane. In addition, the effect of system parameters, such as temperature, pH value, vesicle size, and thickness of the vesicle membrane, was studied.