Well-defined tertiary amine-based pH-responsive homopolymers and block copolymers were synthesized via reversible addition-fragmentation chain transfer (RAFT) polymerization using 4-cyanopentanoic acid dithiobenzoate (CPAD) as the RAFT agent for homopolymers and a poly(ethylene glycol) (PEG) macro-RAFT agent for the block copolymers. H-1 NMR and gel permeation chromatography results confirmed the successful synthesis of these homopolymers and block copolymers. Kinetics studies indicated that the formation of both the homopolymers and the block copolymers were well defined. The pKa titration experiments suggested that the homopolymers and the related block copolymers have a similar pKa. The dynamic light scattering investigation showed that all of the block copolymers underwent a sharp transition from unimers to micelles around their pKa and the hydrodynamic diameter (D-h) was not only dependent on the molecular weight but also on the composition of the block copolymers. The polymer solution of PEG-b-PPPDEMA formed the largest micelle compare to the PEG-b-PDPAEMA and PEG-b-PDBAEMA with a similar molecular weight. (c) 2015 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2015, 53, 1010-1022