Induced twisting in the self-assembly of chiral Schiff-based rod-coil amphiphiles

Abstract

A series of novel organic superstructures exhibiting diverse aggregate morphologies with liquid-crystalline-like properties were prepared by a simple precipitation method. Here, a chiral sugar moiety was simply introduced at the Schiff-based rod end of rod-coil molecules. In contrast to coil-coil molecules, the self-assembled rod-coil molecules exhibit a high segregation strength for phase separation because of their liquid-crystalline-like behavior. The morphological transformation of self-assembled chiral Schiff-based rod-coil amphiphiles, from a platelet-like morphology to helical twists, was obtained by increasing the length of the hydrophobic tail. Consistent with theoretical predictions, the bending force from the chiral entity depends on the size of the adjacent hydrophobic tail. That is, the size of hydrophobic chain determines the threshold of bending for the formation of a helical morphology. Moreover, by introducing an additional tethered hydrophobic chain self-assembled spherical vesicles can be obtained through the collapse of the twisted shape.