Phosphorescence-probed study on the association of surfactants with β-cyclodextrin

The formation of association complexes between surfactants (S) and β-cyclodextrin (β-CD) has been studied using 1-bromonaphthalene (1-BrN) as a phosphorescent probe. In combination with the spectral structure, phosphorescence lifetimes, surface tension of solutions and association constants of 1:1:1/S:1-BrN:β-CD complexes, a comparison of molecular size shows that the hydrocarbon chain of surfactants is partly included in the cavity of β-CD and the hydrophobic part with the polar head group is located outside the cavity coils at the mouth of the β-CD cavity.