Self-assembly of vesicles from amphiphilic aromatic amide-based oligomers

A novel class of linear arylamide oligomers has been designed and synthesized from naphthalene-2,7-diamine and benzene-1,3,5-tricarboxylic acid segments. The molecules carry two (tert-butoxycarbonylamino) groups at the ends and one to three hydrophilic N,N-bis(2-(2-(2-methoxyethoxy)ethoxy)ethyl)amino groups at one side of the backbone. The oligomers self-assembled into vesicular structures in methanol as a result of ordered stacking of the oligomeric amide backbones, which were evidenced by SEM, AFM, TEM, and fluorescent micrography experiments. It was also found that the tert-butoxycarbonylamino groups at the ends played an important role in promoting the ordered stacking of the backbones. Structural factors that affected the self-assembly of the oligomers were investigated. A two-layer model that was supported by TEM has been proposed for the formation of the vesicular structures, which was driven by both the hydrogen bonding and aromatic stacking.