Bilayers directly scrolling up to form nanotubes via self-assembly of an achiral small molecule

The self-assembly behavior of a molecule composed of an azobenzene segment, carboxylic-acid group and flexible alkyl chains (denoted by ABA11) was studied as an extension of our proceeding work. We have previously reported that in DMSO solution ABA11 self-assembled into nanotubes starting from nanosheets and experiencing a meta-state of helical ribbons. Herein, we found that changing the solvent can also affect the self-assembly pathway of ABA11 to nanotubes. When DMSO was replaced by ethanol, the nanosheets formed by ABA11 bilayers either directly scrolled up to form nanotubes without a meta-state of helical ribbons at low concentrations, or stacked up to form nanobricks at higher concentrations. In addition, increasing the water content in ethanol can significantly facilitate the formation of the assembled nanostructures.