Supramolecular hydrogel formation based on inclusion complexation between poly(ethylene glycol)-modified chitosan and...

Area of Science:

• Materials Science
• Polymer Chemistry
• Supramolecular Chemistry

Background:

• Chitosan-based hydrogels are extensively researched for various applications.
• Developing novel supramolecular hydrogels with tunable properties is an active area of research.
• Polymer inclusion complexes (PICs) offer a promising route for creating advanced hydrogel systems.

Purpose of the Study:

• To synthesize and characterize supramolecular hydrogels based on poly(ethylene glycol) (PEG)-modified chitosans and alpha-cyclodextrin (alpha-CD).
• To investigate the formation mechanism and structural properties of these novel hydrogels.
• To explore the thermo-reversible gel-sol transition behavior of the developed hydrogels.

Main Methods:

• Synthesis of PEG-modified chitosans using carbodiimide coupling.
• Hydrogel formation via simple mixing of polymers and alpha-CD in aqueous media.
• Characterization using differential scanning calorimetry (DSC), X-ray diffraction, and NMR spectroscopy.

Main Results:

• Successful formation of supramolecular hydrogels through PICs between PEG-modified chitosan and alpha-CD.
• Confirmation of channel-type crystalline micro-domains formed by inclusion complexes (ICs) of PEG and alpha-CD.
• Demonstration of thermo-reversible gel-sol transitions in acidic conditions, driven by supramolecular association and dissociation.

Conclusions:

• PEG-modified chitosan and alpha-CD effectively form supramolecular hydrogels via PICs.
• The IC domains act as physical cross-linking points, enabling hydrogel formation.
• These hydrogels exhibit tunable thermo-reversible properties, indicating potential for smart material applications.