Formation of Supramolecular Gels from Host–Guest Interactions between PEGylated Chitosan and α‐Cyclodextrin

Chitosan‐based hydrogels are prepared via the formation of polypseudorotaxanes (PPR), by selectively threading α‐cyclodextrin (α‐CD) macrocycles onto polymeric chains, which, through the formation of microcrystalline domains, act as junction points for the network. Specifically, host–guest inclusion complexes are formed between α‐CD and PEGylated chitosan (PEG‐Ch), resulting in the formation of supramolecular gels. PEG‐grafted chitosan is obtained with a reaction yield of 79.8%, a high degree of grafting (50.9% GW) and water solubility (≈16 mg mL−1), as assessed by turbidimetry. A range of compositions for mixtures of PEG‐Ch solutions (0.2–0.8% w/w) and α‐CD solutions (2−12% w/w, or 0.04–0.2% mol) are studied. Regardless of PEG content, gels are not formed at low α‐CD concentrations (