Alkyl-poly(l-threonine)/Cyclodextrin Supramolecular Hydrogels with Different Molecular Assemblies and Gel Properties

We report alkyl-poly(l-threonine)/cyclodextrin (alkyl-PLT/CD) supramolecular hydrogels with different molecular assemblies. Their properties are determined by the interplay between host-guest chemistry and hydrogen-bonding interactions. The gelation process was mainly dictated by the formation of alkyl chain/CD inclusion complex and PLT chain conformation. The dodecyl-PLT₂₀/α-CD hydrogel exhibited laminar packing due to the sheet-to-coil conformational change upon forming inclusion complex. The hexadecyl-PLT₂₀/β-CD hydrogel exhibited ribbon-like assemblies instead, because the peptide adopted mainly sheet conformation. The gel-to-sol transition occurred upon increasing temperature because of the decrease in hydrogen-bonding interactions and partly conformational change.