Hyperbranched polymers have received considerable attention in recent years due to their unusual properties arising from their unique molecular architecture and convenient synthesis by one-step polymerization of AB_m（m ≥ 2） type monomers. However, hyperbranched polymers obtained by general synthetic methods have two disadvantages.
First, the branching structure is not perfect; polymer topology is not well controlled. Second, the molecular weight is also not well controlled, and the molecular weight distribution is broad. These defects stem from the fact that the AB_m monomers are generally polymerized by polycondensation or polyaddition, which proceeds through a step-growth polymerization mechanism. Herein we describe a new approach to controlled polymerization of AB₂ monomer from a core molecule in a chain-growth polymerization manner by using the change of substituent effects between the monomer and the polymer. Furthermore, properties of the obtained hyperbranched polyamides, synthesis and selfassembly of well-defined polystyrene-b-hyperbranched polyamides were also investigated.