2-(Dimethylamino)ethyl methacrylate (DMA) was block copolymerized in turn with three other tertiary amine methacrylate comonomers, namely, 2-(diethylamino)ethyl methacrylate (DEA), 2-(diisopropylamino)ethyl methacrylate (DPA), and 2-(N-morpholino)ethyl methacrylate (MEMA), using group transfer polymerization. The DMA residues of each of these diblock copolymers were selectively quaternized using both methyl iodide and benzyl chloride under mild conditions to yield a series of novel cationic diblock copolymers that exhibit reversible pH-, salt-, and temperature-induced micellization in aqueous media.