Reverse iodine transfer polymerization (RITP), offering the appealing potential of the in situ generation of transfer agents out of molecular iodine I-2, is employed in the synthesis of anionic amphiphilic diblock copolymers of poly(styrene) and poly(acrylic acid). Starting with well-characterized poly(styrene) as macro-transfer agents synthesized by RITP, diblock copolymers poly(styrene)-b-poly(tert-butyl acrylate) of various lengths are successfully yielded in solution with a good architectural control. These blocks are then subjected to acid deprotection and subsequent pH control to give rise to anionic amphiphilic poly(styrene)-b-poly(acrylic acid). Besides, homopolymers of tert-butyl acrylate are produced by RITP both in solution and in emulsion. Furthermore, a fruitful trial of the synthesis of diblock copolymers poly(tert-butyl acrylate)-b-poly(styrene) is carried out through chain extension of the poly(tert-butyl acrylate) latex as a macro-transfer agent in seeded emulsion polymerization of styrene. Finally, the prepared block copolymer is deprotected to bring about its amphiphilic nature and a pH control caters for its anionic character. (c) 2013 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2013, 51, 4389-4398