Self-assembly of peptide-based diblock oligomers

The synthesis and supramolecular organization of a novel class of rod-coil type diblock oligomers will be discussed. The diblock oligomers consist of a rodlike alpha -helical oligopeptide segment that is conjugated to an olig o(styrene) coil. In comparison with most of the rod-coil type oligomers tha t have been investigated so far, these peptide-based diblock oligomers poss ess some unique features: (i) the conformation of the oligopeptide rod segm ent can be reversibly manipulated under the action of appropriate external stimuli, and (ii) the self-assembly of these molecules is (also) driven by directed hydrogen-bonding interactions. The diblock oligomers are prepared by ring-opening polymerization of gamma -benzyl-L-glutamate N-carboxyanhydr ide using a primary amine-terminated oligo(styrene) as the initiator. The d iblock oligomers form thermotropic liquid-crystalline phases, whose supramo lecular organization depends both on the relative block-lengths and on the conformation of the peptide segment.