Dibenzyltrithiocarbonate-mediated RAFT polymerization of dimethyl-p-vinylbenzylphosphonate and its copolymerization with styrene are studied in order to access well-defined statistical and block copolymers containing controlled amounts of dimethylphosphonate groups. NMR and SEC analysis of the (co)polymers confirm the controlled character of the polymerizations. ABA triblock copolymers are treated with TMSiBr/MeOH in order to transform the dimethylphosphonate groups into phosphonic acids while keeping the midchain trithiocarbonate group and triblock nature unaffected. Alternatively, the combination of trithiocarbonate aminolysis with TMSiBr/MeOH treatment of the same triblock copolymers leads to phosphonic acid-functional diblock copolymer counterparts. (C) 2014 Wiley Periodicals, Inc.