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A series of polyacrylate-polystyrene-polyisobutylene-polystyrene-polyacrylate (X-PS-PIB-PS-X) pentablock terpolymers (X ¼ poly(methyl acrylate) (PMA), poly(butyl acrylate) (PBA), or poly(methyl methacrylate) (PMMA)) was prepared from poly (styrene-b-isobutylene-b-styrene) (PS-PIB-PS) block copolymers (BCPs) using either a Cu(I)Cl/1,1,4,7,7-pentamethyldiethylenetriamine (PMDETA) or Cu(I)Cl/tris[2-(dimethylamino)ethyl]amine (Me 6 TREN) catalyst system. The PS-PIB-PS BCPs were prepared by quasiliving carbocationic polymerization of isobutylene using a difunctional initiator, followed by the sequential addition of styrene, and were used as macroinitiators for the atom transfer radical polymerization (ATRP) of methyl acrylate (MA), n-butyl acrylate (BA), or methyl methacrylate (MMA). The ATRP of MA and BA proceeded in a controlled fashion using either a Cu(I)Cl/PMDETA or Cu(I)Cl/ Me 6 TREN catalyst system, as evidenced by a linear increase in molecular weight with conversion and low PDIs. The polymerization of MMA was less controlled. 1 H-NMR spectroscopy was used to elucidate pentablock copolymer structure and composition. The thermal stabilities of the pentablock copolymers were slightly less than the PS-PIB-PS macroinitiators due to the presence of polyacrylate or polymethacrylate outer block segments. DSC analysis of the pentablock copolymers showed a plurality of glass transition temperatures, indicating a phase separated material.