Surfactant–cyclodextrin interactions by conductance measurements

Abstract

Conductance measurements were used to identify and to obtain association constants for the complexes formed between cyclodextrins (CD) with emphasis on β-cyclodextrin (βCD), and surfactants such as sodium dodecylsulfate (SDS) and tetradecyltrimethyl ammonium bromide. With both anionic and cationic surfactants, αCD forms predominantly a 2:1 CD/surfactant complex while with both βCD and γCD the main species is 1:1. γCD binds much less strongly with surfactants than both αCD and βCD. Cyclodextrins destroy micelles by complexing the surfactant monomers more strongly than they are bound in self-association.