Roles of oleic acid during micropore dispersing preparation of nano-calcium carbonate particles

► Nano-CaCO3 particles have been successfully prepared by micropore dispersion method. ► Oleic acid is introduced as surfactant during micropore dispersion preparation. ► The addition of oleic acid can reduce the size of nano-CaCO3 particles. ► Two opposite roles of oleic acid in the preparation of CaCO3 are concluded.