Studies and comparison of the liquid adsorption and surface properties of α-, β- and γ-cyclodextrins by FTIR and capillary rise method

The liquid adsorption behavior and surface properties of α-, β-, and γ-cyclodextrin, CD, were studied and compared by FTIR and capillary rise method. These three CDs all showed an intense peak at 1155 cm−1 due to the C–O structure stretching and the peak height was found to reduce with the sugar ring molecules of CD increase. All these three CDs adsorbed the non-polar liquids greatly as compared with the polar liquid due to their total surface free energies dominated by the Lifshitz–van der Waals interactions component. The increase of the sugar ring molecules has been found to increase the Lewis acid–base property of CDs.