Multiple hydrogen bonding induced self-assembly: transformation from nanofibrils to nanosphere with aromatic oligoamide incorporated polyethylene glycol

Aromatic oligoamides bearing six potential hydrogen-bonding sites were designed and synthesized. Functionalized with two polyethylene glycol (Mw = 2000), this aromatic oligoamide could self-assemble via hydrogen bonds to form nanofibrils in nonpolar solvents as a result of aggregation. The resulting aggregates were characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM) and dynamic light scattering (DLS). Upon adding another aromatic oligoamide containing complementary hydrogen bond donors and acceptors, transformation from nanofibrils to nanosphere was observed due to formation of hydrogen-bonded duplex. The nanospherical micelle was corroborated by SEM, transmission electron microscopy (TEM) and AFM tests. The results achieved here demonstrate an alternative route to effect supramolecular structures via multiple hydrogen bonding-induced self-assembly process.