Synthesis and Surface Properties of N,N-Dimethyl-N-dodecyl Polyoxyethylene Amine-Based Surfactants: Amine Oxide, Betaine and Sulfobetaine

Nonionic–zwitterionic hybrid surfactants, namely N,N-dimethyl-N-dodecyl polyoxyethylene (3) amine oxide, and the corresponding betaine and/or sulfobetaine, have been synthesized. Their molecule structures were characterized by means of electrospray ionization mass spectrometry and 1H nuclear magnetic resonance. Compared to the structurally related conventional amine oxide, betaine and sulfobetaine, the critical micelle concentrations of the three hybrid surfactants are one order of magnitude smaller than those of traditional ones. The polyoxyethylene segment between the hydrophilic head group and the hydrophobic tail makes the surface activities of the hybrid surfactants superior to their structure-related counterparts.