Deep Eutectic Supramolecular Polymers: Bulk Supramolecular Materials

Abstract

Application of new strategies for supramolecular self‐assembly can significantly impact the properties and/or functions of supramolecular polymers. To realize a facial strategy for the development of solvent‐free supramolecular polymers in bulk, “deep eutectic solvents” were employed. Cyclodextrins and natural acids were used to prepare deep eutectic supramolecular polymers (DESPs). Deep eutectic solvents have special characteristics that endow DESPs with unique macroscopic properties and excellent processability. DESPs exhibit supramolecular adhesion and temperature‐dependent behavior originating from the combined effects of deep eutectic solvents and supramolecular polymerization. Because DESPs are solvent‐free and display interesting macroscopic properties, they have potential as new adaptive materials.

Supramolecular Adhesive Materials from Natural Acids and Sugars with Tough and Organic Solvent-Resistant Adhesion

“…43,45,46 Temperature-induced transitions from mixtures of nonsticky solids to highly viscous soft materials were observed ( Figure 1b and Supporting Information Videos S1 and S2), indicating the occurrence of supramolecular polymerization between the sugars and acids. 9 In constrast, individual acids or sugars were nonviscous and did not show any adhesion effect. Compared with the 1 H NMR spectra of the simply mixed sugars and acids, no changes were observed in the 1 H NMR spectra of deep eutectic supramolecular adhesive materials ( Figure 1b and Supporting Information Figures S2-S13), which demonstrated that no esterification or etherification took place at 60°C.…”

“…4,5 Supramolecular polymer structures and hydrogen bond formation give rise to the cohesive and adhesive properties. [6][7][8][9] However, water can be easily removed from the sugar-water supramolecular polymeric systems during the practical adhesion process, thus leading to a significant attenuation of adhesion strength or adhesion effect. 10,11 With the rapid development of artificial polymeric adhesives in the past century, natural adhesives were no longer the research focus of modern adhesives.…”

“…[43][44][45][46] In our previous work, we developed cyclodextrin-acid supramolecular adhesives. 9 However, the combination of DESs, adhesion, and supramolecular polymerization represents a new but still rarely acknowledged method to prepare supramolecular adhesives. 9,38,45 Here, we report a series of acid-sugar adhesive materials that exhibit tough and long-term adhesion effects on various surfaces.…”

“…9 However, the combination of DESs, adhesion, and supramolecular polymerization represents a new but still rarely acknowledged method to prepare supramolecular adhesives. 9,38,45 Here, we report a series of acid-sugar adhesive materials that exhibit tough and long-term adhesion effects on various surfaces. Kilogram-scale and eco-friendly adhesives were prepared in a facile route.…”

“…The hydrogen bond formation between sugars and acids leads to the fabrication of supramolecular polymers, which dramatically improves the adhesion capacity and sustainability. 9,39,40,41 Strong, recyclable, and long-term adhesion performance on a wide range of substrates originate from the reversible hydrogen bonding and dynamical supramolecular polymerization. 42 Importantly, acid-sugar adhesive materials are highly resistant to organic solvents, and tough adhesion behavior is easily achieved in various organic solvents.…”