Polyurethane macroiniferter (PUMI) including tetraphenylethane was synthesized and used to prepare polyurethane-polyacrylic acid multiblock copolymers. Film-forming aqueous dispersions without any added external emulsifiers were prepared from polyurethane-polyacrylic acid multiblock copolymers. The effect of varying PUMI content, polymerization time, and percent ionization on the properties of multiblock copolymeric dispersions were studied in detail. Interfacial tension of the dispersions and critical surface tension measurements of the films formed thereof have shown that the polymers exhibit a hydrophilic character in the dispersed phase and a hydrophobic character in the solid phase.