A study of the properties of the 1:1 inclusion complex of β-cyclodextrin with cetyltrimethylammonium bromide

The properties of the 1:1 inclusion complex of β-cyclodextrin (β-CD) with cetyltrimethylammonium bromide (CTAB) were investigated by pyrene and 1-pyrene butyric acid fluorescence. It is shown that in the 1:1 CTAB/β-CD inclusion complex the hydrophobic alkyl chain is included in the β-CD cavity, with the majority of the chain protruding into the bulk phase with the counterion binding to the polar head. In aqueous solution this 1:1 CTAB/β-CD inclusion complex aggregates and micellizes into micelles of which the interior hydrophobic region (the Stern layer and micelle core) is less polar than that of CTAB and its critical micelle concentration is 2.05 × 10−3 mol l−1, which is in agreement with the value determined by surface tension.