Adsorption of calixarene-based supramphiphiles at the solid–liquid interface monitored by QCM-D

Supramolecular amphiphiles are a topic of widespread interest in supramolecular chemistry and the characterisation of their properties at the interfacesis at the basis of industrial and biotechnology applications. This work focuses on the determination of the adsorption features of supramolecular amphiphiles, formed by the host-guest complexation of a p-sulfonatocalix[4]arene with selected cationic surfactants, at the solid–liquid interface monitored by quartz crystal microbalance with dissipation monitoring (QCM-D) experiments. The adsorption process resulted to be favourite and strongly affected by the length of the surfactant alkyl chain and somehow by the nature of the polar head. The adsorption isotherms highlighted the key role played by the calixarene scaffold in the CMC value, the amount of material absorbed and the efficiency of the adsorption process on a gold substrate. Furthermore, the kinetic profiles provided significant insights on the different mechanisms of adsorption undergone by either conventional or supramolecular amphiphilic systems.