Characterization of β-cyclodextrins and isosorbide diesters self-assemblies: Towards new renewable surfactants

A series of isosorbide diesters and cyclodextrins were attempted to create host-guest surfactants. The interaction between these host and guest molecules was investigated by NMR, DSC and optical microscopy. Only the isosorbide esters with alkyl chains ranging from C10 to C18 form stables inclusion complexes with the native β-cyclodextrin. Molecular dynamics calculations were also made to better understand the nature of the supramolecular edifices formed and hydrogen bonds between several native cyclodextrins are thought to be involved in the stability of the inclusion complexes. With the randomly methylated cyclodextrin (RAME-β-CD), the results were clearly different. Due the methylation of the hydroxyl groups, the RAME-β-CD could not form stable inclusion complex with the longer diesters. However, when short isosorbide diesters were mixed with an aqueous solution of RAME-β-CD, a solubilization of the esters was observed and a decrease of surface tension was noticed.