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

Abstract

Summary: The inclusion of polymer chains by cyclodextrins (CDs) may generate column‐like supramolecules. Herein, we report that the selective threading of cyclodextrin rings onto one segment of a double hydrophilic diblock copolymer in water generates spherical aggregates. Poly(ethylene oxide)‐block‐poly((dimethylamino)ethyl methacrylate) (PEO‐b‐PDMA) may dissolve in water to form a homogeneous solution. However, when α‐CDs are introduced, they thread onto the PEO segments to form pseudopolyrotaxanes, which tend to aggregate. Instead of forming a precipitate, novel supramolecular particles are generated which are attributed to the stabilization of the soluble PDMA segments. The organization process and the assembly structure were characterized by dynamic light scattering, X‐ray diffraction, electron microscopy and 1D NOE NMR spectra. Such novel particles are biocompatible and could have potential applications as biomedical and stimulus‐response materials.Schematic presentation of the self‐assembly process.magnified imageSchematic presentation of the self‐assembly process.

pH‐/temperature‐sensitive supramolecular micelles based on cyclodextrin polyrotaxane

“…Consequently, it has been considered that the PR aggregation might become the driving forces of micellar assembly in aqueous media while the uncovered hydrophilic segments play a role in stabilizing the assemblies. Recently, we have reported temperature‐sensitive supramolecular nanoaggregates organized from a double‐hydrophilic block polymer, PEO‐ block ‐poly(dimethylaminoethyl methacrylate) (PEO‐ block ‐PDMA), and α‐CD 20. Although the PR stacking was ill‐formed, a few PRs based on α‐CDs threaded on PEO induced the affiliation of free α‐CD and then became cores for the organization of spherical nanoparticles 20.…”

Multi-morphological self-assembled structures of a rod-coil organometallic oligomer

“…However, a new diffraction peak at 2θ020° (Fig. 5c) identical with the channel crystalline structure of α-CD beside of the characteristic peaks of PEG segments was appeared in the X-ray diffraction pattern of sample FcBA-PEG 17 /α-CD, indicating that α-CD threaded onto the PEG chains could stack on top of each other to form channels in which the guest molecules reside [34][35][36][37][38]. The channeltype structure is hydrophobic and rigid.…”

Supramolecular Polymers Based on Cyclodextrins for Drug and Gene Delivery

“…a-CD was able to thread over the PEG segment, but not the PDMA segment of this polymer axle. The threaded part of the polypseudorotaxanes aggregated, leaving the hydrophilic PDMA polymers exposed to solution, thus forming a micellar structure [73]. Recently, suparmolecular aggregates possessing pH-induced reversible micellegel transition were synthesized.…”