Supramolecular self-assembly of 14-helical nanorods with tunable linear and dendritic hierarchical morphologies

Bioinspired self-assembly offers a way to create novel functional materials from simple, easy-to-synthesize building blocks. Peptides, in particular, are frequently used in the design of self-assembled materials for their structural properties and the ability for supramolecular "lock and key'' type recognition based on H-bonding networks and dispersion interactions. We have previously reported the head-to-tail self-assembly of N-terminal acetylated beta-peptides into helical fibrils through a supramolecular three point H-bonding motif, and the superstructures formed from inter-fibril interactions. Here we show that the superstructure morphology of a self-assembled beta(3)-peptide, Ac-beta(3)[LIA], can be tuned to present a range of morphologies by the appropriate solvent medium. From the same monomer we succeeded in creating straight compact "nano-beams'', self-spun threads and complex, dendritic, hierarchical structures. The variation in geometries is therefore achieved through careful switching and tuning of the relative strengths of the inter-fibril H-bonding, van der Waals and solvophobic interactions.