Surgace tension studies of lauryl sulfobetaine-#beta#-cyclodextrin and dodecyltrimethylammonium bromide-#beta#-cyclodextrin inclusion complexes in aqueous solution

摘要

#beta#-Cyclodextrin (#beta#-CD) is a cyclicoligosaccaride with an apolar cavity that shows a certain degree ofselectivity in binding organic and inorganic compounds. Laurylsulfobetaine (LSB) and dodecyltrimethylammonium bromide(DTAB), having the same hydrophobic and different polar groupsare used in order to compare the influence of the polar group oncomplex formation with #beta#-CD. The surface tension increasedas #beta#-CD is added to premicellar region of amphoteric (LSB)and cationic surfactant (DTAB) solutions. The relation betweenthe surface tension and surfactant concentration can be expressedby the Szyszkowski equation, which combines the Langmuiradsorption model and the Gibbs equation. Binding constants weredetermined from the effect of added #beta#-CD on the surfacetension vs. Concentration curves for LSB and DTAB aqueous solutions.