Preparation and Supramolecular Self-Assembly of a Polypeptide-block-polypseudorotaxane

We have successfully prepared a new class of self-assembled biomaterial: a polypeptide- block -polypseudorotaxane diblock copolymer. This diblock copolymer is comprised of an α-helical polypeptide rod, based on γ-benzyl- l -glutamate, and an originally coiled segment P(EO 19 - r -PO 3 ); it forms inclusion complexes with α-cyclodextrins (α-CDs) to give crystalline polypseudorotaxanes. Formation of the polypseudorotaxane converts the conformation of P(EO 19 - r -PO 3 ) from a flexible chain into a rodlike structure, which results in a novel block copolymer exhibiting a rod−rod conformation. Intrinsic interactions (e.g., the polypseudorotaxane's channel-type crystallization, the polypeptide's secondary structure, and microphase separation) within and between these rod−rod diblock copolymers contribute to their hierarchical self-assembly behavior, which we characterized using DSC, 1 H NMR spectroscopy, 13 C CP/MAS NMR spectroscopy, WAXS, and SAXS. The data obtained from the WAXS and SAXS studies clearly indicate the formation of juxtaposed bilayer-like nanostructure featuring hexagonally packed PBLG stacks and channel-type polypseudorotaxane moieties.