A polyisoprene-block-poly(2-cinnamoylethyl methacrylate) (PI-b-PCEMA) sample with 88 units of isoprene and 2.3 x 10(2) units of CEMA formed vesicles in THF/hexanes with hexanes volume fractions between 50% and 95%. The vesicles had PCEMA as the shell and PI chains stretching into the solution phase from both the inner and outer surfaces of the PCEMA shell. The cavity diameter of the vesicles is similar to 38 nm, and the volume fraction of PI chains there is low. After the PCEMA shell was cross-linked, the PI chains were converted to water-soluble poly(2,3-dihydroxyl-2-methyl-butane) chains. The water-soluble hollow nanospheres uptook a large amount of rhodamine B in methanol and released the compound into water at a tunable rate depending on the amount of ethanol added to the aqueous medium. This study demostrates the potential of hollow nanospheres, prepared from tailor-made biocompataible and degradable polymers, as drug carriers in controlled drug release applications.