Multiple Stimuli-Responsive Supramolecular Hydrogels Constructed by Decamethylcucurbit[5]uril-para-phenylenediamine Exclusion Complex

Abstract

The hydrogels composed of decamethylcucurbit[5]uril (Me₁₀ Q[5]) and para-phenylenediamine (p-PDA) are first reported herein. They are the first Q[5]-based supramolecular hydrogels, the formation of which is driven by portal exclusion between Me₁₀ Q[5] and p-PDA. The composition, structure, and properties of the Me₁₀ Q[5]/p-PDA-based hydrogels are investigated by various techniques. Since the 1D supramolecular chain forms via portal exclusion between Me₁₀ Q[5] and p-PDA is the key to the formation of the hydrogels, any competitive species, such as metal ions, organic molecules, and amino acids, which can affect the portal exclusion, can change the behavior of the Me₁₀ Q[5]/p-PDA-based hydrogels. Hence, the hydrogels can be used for various applications. Importantly, the results may provide a new research direction for the preparation of Q[n]-based hydrogels via portal exclusion of Q[n]s with guests.

Keywords: decamethylcucurbit[5]uril; exclusion complexes; hydrogel response; para-phenylenediamine.