Atom transfer radical polymerization with activators generated by electron transfer initiating/catalytic system (AGET ATRP) of 2-hydroxyethyl methacrylate (HEMA) was carried out in inverse miniemulsion. Water-soluble ascorbic acid as a reducing agent and mono-and difunctional poly(ethylene oxide)-based bromoisobutyrate (PEO-Br) as a macroinitiator were used in the presence of CuBr2/tris[(2-pyridyl)methyl]amine (TPMA) and CuCl2/TPMA complexes. The use of poly(ethylene-cobutylene)-block-poly(ethylene oxide) as a polymer surfactant resulted in the formation of stable HEMA cyclohexane inverse dispersion and PHEMA colloidal particles. All polymerizations were well-controlled, allowing for the preparation of well-defined PEO-PHEMA and PHEMA-PEO-PHEMA block copolymers with relatively high molecular weight (DP > 200) and narrow molecular weight distribution (M-w/M-n < 1.3). These block copolymers self-assembled to form micellar nanoparticles being 1020 nm in diameter with uniform size distribution, and aggregation number of similar to 10 confirmed by atomic force microscopy and transmission electron microscopy. (c) 2007 Wiley Periodicals, Inc.