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

Abstract

We have successfully prepared a new class of self-assembled biomaterial: a polypeptideblock-polypseudorotaxane diblock copolymer. This diblock copolymer is comprised of an R-helical polypeptide rod, based on γ-benzyl-L-glutamate, and an originally coiled segment P(EO19-r-PO3); it forms inclusion complexes with R-cyclodextrins (R-CDs) to give crystalline polypseudorotaxanes. Formation of the polypseudorotaxane converts the conformation of P(EO19-r-PO3) 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.

Synthesis of achiral PEG‐PANI rod‐coil block copolymers and their helical superstructures

“…Some effort had been made to synthesize amphiphilic block polymer and to study the formation of the helical superstructure by means of self‐assembly 2, 3. Also other block polymers had been synthesized to form the helical superstructures recently 4, 5. However, most of the studies had utilized at least one segment of chiral groups in the block 6, 7.…”

Recent SAXS progress at NSRRC

“…The SAXS/WAXS result revealed clearly the correlation between the formation of juxtaposed bilayer-like nanostructure with the formation of hexagonally packed PBLG stacks and channel-type polypseudorotaxane moieties. 11 In the last example, we would like to show a unique feature of using synchrotron X-ray for ASAXS at the NSRRC, in a structural study of Pt nanoparticles embedded in carbon matrix. The Pt/C system is considered as an effective catalytic electrode in the application of DMFC.…”

Hydrophilic Block Copolymer Aggregation in Solution Induced by Selective Threading of Cyclodextrins

“…This kind of hydrogel undergoes a gel to sol transition on elevating the temperature and the process is reversible due to the dynamic character of the host‐guest interaction. Among the guest polymers studied, block copolymers threaded by CDs have been reported by several groups 23–34. However, these works focus on how the properties of bulk materials are regulated by the inclusion.…”

“…However, these works focus on how the properties of bulk materials are regulated by the inclusion. For example, selective threading onto one segment of block copolymers can change the microphase structure of the bulk state 27–30. Also, the interaction of CDs and biodegradable block copolymers may regulate the degradability of the copolymers 31.…”