Synthesis and Surface Activity of Guerbet Betaine Surfactants with Ethylene Oxide Groups

Three series of Guerbet betaine surfactants with ethylene oxide groups were synthesized by Guerbet alkyl polyoxyethylene ether surfactants, epichlorohydrin, dimethylamine and sodium chloroacetate. Their structures were confirmed by MS. The critical micelle concentrations (CMC) and surface tension at CMC (gamma(CMC)) of all prepared Guerbet betaine surfactants were determined by K100C processor tensiometer with the Wilhelmy-plate method at 25 degrees C. It is found that synthesized surfactants exhibit great efficiency of reducing surface tension. As the number of ethylene oxide groups increases, the gamma(CMC) gradually increases. As the length of the hydrophobic chain of Guerbet betaine surfactants increases, the gamma(CMC) increases firstly and then decreases.