Construction Of Giant Branched Nanotubes From Cyclodextrin Based Supramolecular Amphiphiles

Molecular self-assembly, which is very common in nature, plays animportant role in the formation process of many highly organized andfunctionalized biological macromolecules such as viruses, cytomembranes.Inspired by the wisdom of nature, a tremendous effort has been devoted todesigning complicated nanostructures in the past decades. Supramolecularamphiphiles with the advantage of easy preparation and low cost attractedconsiderable attention. So far, researchers have assembled a variety ofconfigurations, for example, vesicles, nanorings, nanofibers and micelles. Theexciting morphologies mainly depend on the architecture of molecules and thenoncovalent driving forces, such as Π-Π interaction, hydrogen bonding, metal–ligand coordination, electrostatic attraction, charge transfer interaction, and host–guest recognition. However, it is still a great challenge to see how to utilize thedriving forces discovered to construct more sophisticated nanostructures.In the year of1984, the research groups from Japan and America nearly atthe same time discovered that lipid molecules could assembled into lipidnanotubes. After that, carbon nanotubes were firstly discovered by Iijima in1991.Then, the novel tubular structures with the special architectures arousedresearchers’ attention. The methods to construct nanotubes as follows: packing-directed self-assembly, polymer assembly, chiral molecular self-assembly,templated synthesis using a pore and molecular sculpting. However, it is still agreat challenge to see how to control the growing direction of nanotubes.The supramolecular amphiphiles formed by cyclodextrin and adamantanol-1-3,4,5,-trihydroxybenzoicammide could self-assemble into nanotubes in water.Basing on this, disulfides linked β-CD dimmer was introduced into the self-assembly system. As the disulfides linked β-CD dimer has two differentmolecular conformations owing to the wiggle of disulfide bonds:‘head to head’and ‘shoulder to shoulder’, we successfully got the giant branched nanotubes.We realize the control of the extent of nanotube branching by changing the amount of CD-S-S-CD in the host molecules. Meanwhile, this approach of constructingbranched nanotubes is simple, economical, and environmentally benign. It isanticipated that this new finding will provide a new strategy for constructingother more nanostructures.