Preparation of ultrasmall cyclodextrin nanogels by an inverse emulsion method using a cationic surfactant.

Stable water-in-oil emulsion membranes can be prepared using [dilauryl(dimethyl)ammonium] bromide (DDAB), a cationic surfactant. We prepared ultrasmall cyclodextrin (γ-CyD) nanogels (γ-CyDngs) by forming ionic pairs between the secondary hydroxyl groups of γ-CyDs and DDAB. Fluorescence and NMR characterisation of the obtained γ-CyDngs revealed superior inclusion affinities compared with native γ-CyDs, beneficial for the solubilisation of hydrophobic compounds in water.