Vesicles and organogels from foldamers: A solvent-modulated self-assembling process

Nonamphiphilic, hydrogen-bonded hydrazide foldamers appended with four or six long flexible chains were revealed to spontaneously assemble to form vesicles in methanol and organogels in aliphatic hydrocarbons. SEM, AFM, TEM, DLS, and fluorescence microscopy were all used to identify the structures of the vesicles. It was proposed that intermolecular pi stacking of the folded frameworks and hydrogen bonding of the amide units in the appended chains induced the molecules to produce cylindrical aggregates. In polar methanol, these aggregates packed together to generate one-layered vesicles owing to hydrophobically induced entanglement of the peripheral chains, while in nonpolar hydrocarbons, the peripheral chains entwined across stacked cylinders to form three-dimensional networks and thus immobilize the liquid molecules.