Molecular assemblies of diazafluorenone Schiff-base amphiphiles. II. The vesicle and its molecular aggregation behavior

The self-assembling properties of a series of single-chain (C12–C18) amphiphilic ligands, diazafluorenone Schiff bases (DAFSB), were studied in dilute aqueous solutions by various physical methods. Transmission electron microscopy (TEM) shows that these amphiphiles can form vesicles with diameters of 50–250 nm and layer widths of about 5 nm. UV-vis spectra reflect the formation of J-like aggregates in bilayer assemblies. The gel to liquid-crystal phase-transition behavior of the bilayer in vesicles was investigated by differential scanning calorimetry (DSC), and the phase transition temperature,Tm, ranged between 60 and 75 °C. The experimental results indicate that DAFSB is a new type of bilayer-forming agent and provides a good model system for studying the interactions between metal ions and amphiphiles.