Green materials with promising applications: cyclodextrin-based deep eutectic supramolecular polymers

Supramolecular polymers (SPs) based on macrocyclic host molecules as copolymer monomers are considered a promising class of advanced materials due to their satisfactory tunable properties and host–guest characteristics. Deep eutectic solvents (DESs) have been developed as green solvents to supersede conventional organic solvents and ionic liquids (ILs). By referring to the formation mechanism and macroscopic properties of DESs, the green strategy to develop solvent-free SPs by incorporating the concept of DESs is considered feasible, which enhances the performance of SPs and requires no solvents. Investigating the combination of DESs and macrocyclic host molecules (represented by cyclodextrins, CDs) to develop deep eutectic supramolecular polymers (DESPs) has been a novel subject in recent years. Researchers have prepared DESPs including supramolecular deep eutectic solvents (SUPRADESs) based on CDs/CD derivatives, supramolecular deep eutectic adhesives/gels, and supramolecular composite materials based on inorganic carrier-modified CDs formed with polymeric DESs (PDESs) and have conducted a preliminary exploration of their properties and applications. Based on the urgent need for further research on the combination of CDs as macrocyclic copolymer monomers and DESs, this review aims to summarize relevant definitions, properties, characterization, and applications of CD-based DESPs that have emerged from recent studies. It is hoped that it would promote the cross-development of green chemistry and supramolecular polymers.