We have synthesized polyaniline (PANI) particles in amphiphilic copolymer micelles. These associative copolymers, hydrophobically end-capped polyurethane resins (HEURs), aggregate in "flower-type" micelles at low concentration and used as a nanoreactor. The prepared PANI particles are "donut-like" shape, and have the typical peaks of UV-vis and FT-IR in emeraldine base (EB) form.