Statistical copolymers of hydroxyethyl methacrylate (HEMA) and (dimethylamino)ethyl methacrylate (DMAEMA) were synthesized by atom transfer radical polymerization (ATRP) at the azeotrope in N,N-dimethylformamide (DMF) with controlled molecular weights and molecular weight distributions (generally < 1.2). Since the polymerization takes place at the azeotrope, the polymer composition is fixed at the monomer feed composition (HEMA molar composition = 0.718), and there is little compositional drift with total monomer conversion. Poly(HEMA-co-DMAEMA) copolymers were also successfully synthesized from a polystyrene macroinitiator previously made by ATRP. Solution-cast thin films of polystyrene-b-poly(HEMA-co-DMAEMA) amphiphilic diblock copolymers exhibit ordered and periodic nanoscale structures with morphologies that depend on the relative volume fractions and casting solvent used.