The syntheses of the ABC and ACB triblock copolymer topological isomers poly(tert-butyl acrylate)-block-polyisoprene-block-polystyrene (ABC) and poly(tert-butyl acrylate)-block-poly-styrene -block-polyisoprene (ACB) using the RAFT-controlled radical polymerization method are described. The triblock copolymers were isolated with molecular weights on the order of 20 000 Da and molecular weight distributions of 1.3-1.5. The polymers described herein demonstrated thermal decompositions at 200 degrees C, characteristic of tert-butyl esters, and their structure and composition were confirmed by a combination of infrared, H-1, and C-13 NMR spectroscopies.