From vesicles to solid spheres: terminal functional group induced morphology modification

Two similar naphthalimide based organogelators were synthesized. These two compounds can gelate a variety of organic solvents and form interesting morphologies. Transmission and scanning electron microscopy of the xerogels of the two compounds showed vesicle and solid sphere morphologies, respectively, even though their molecular structures are very close. The mechanism of the self-assembly process was investigated by H-1 NMR, IR, 2D-NOESY spectra, wide-angle X-ray diffraction and rheological experiments. The study reveals that the cooperation and competition of multiple intra/intermolecular interactions are the main determining factors for these compounds' self-assembly into vesicles and solid spheres. A single functional group able to determine the formation of vesicles in non-typical amphiphilic system is rarely encountered. Therefore, these results provide further insights into morphology control, especially the formation of vesicles in non-typical amphiphilic systems.