Synthesis and ring-opening polymerization of γ-substituted ε-caprolactone monomers containing octyloxy and 2-[2-(2-methoxyethoxy) ethoxy] ethoxy functional groups is reported. An amphiphilic block copolymer containing hydrophobic poly (γ-octyloxy-ε-caprolactone) and hydrophilic poly {γ-2-[2-(2-methoxyethoxy) ethoxy] ethoxy-ε-caprolactone} forms micelles in aqueous solution above the critical micellar concentration of 1.74× 10− 3 g L− ...