CMC of the studied surfactants follow the order: amidobetaine > amidobetaine chloride > amidoamineoxide. The influence of the terminal double bond in the hydrophobic alkyl chain on CMC was also assessed, and a significant increase in CMC was found due to the introduction of the double bond in the cases of amidobetaine chlorides and amidoamineoxides. These two types of surfactants showed higher rigidity