Poly[N-(4-vinylbenzyl)-N,N-dibutylamine hydrochloride] trithiocarbonate, which contains the reactive trithiocarbonate group and the appending surface-active groups, is used as both surfactant and macromolecular reversible addition-fragmentation chain transfer (macro-RAFT) agent in batch emulsion polymerization of styrene. Under the conditions at high monomer content of similar to 20 wt % and with the molecular weight of the macro-RAFT agent ranging from 4.0 to 15.0 kg/mol, well-controlled batch emulsion RAFT polymerization initiated by the hydrophilic 2-2'-azobis(2-methylpropionamidine) dihydrochloride is achieved. The polymerization leads to formation of nano-sized colloids of the poly[N-(4-vinylbenzyl)-N,N-dibutylamine hydrochloride]-b- polystyrene-b-poly[N-(4-vinylbenzyl)-N,N-dibutylamine hydrochloride] triblock copolymer. The colloids generally have core-shell structure, in which the hydrophilic block forms the shell and the hydrophobic block forms the core. The molecular weight of the triblock copolymer linearly increases with increase in the monomer conversion, and the values are well-consistent with the theoretical ones. The molecular weight polydispersity index of the triblock copolymer is below 1.2 at most cases of polymerization. (c) 2012 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2012