Controlling Spatiotemporal Mechanics of Supramolecular Hydrogel Networks with Highly Branched Cucurbit[8]uril Polyrotaxanes. (15th December 2017)

• Record Type: Journal Article
• Authors: Tan, Cindy Soo Yun; Liu, Ji; Groombridge, Alexander S.; Barrow, Steven J.; Dreiss, Cécile A.; Scherman, Oren A.
• Is Part Of: Advanced functional materials. Volume 28:Number 7(2018)
• Page Start: n/a
• Page End: n/a
• Publication Date: 2017-12-15
• Subjects: cucurbit[n]uril -- highly branched polymers -- spatiotemporal networks -- supramolecular hydrogels -- viscoelasticity; Materials -- Periodicals; Chemical vapor deposition -- Periodicals; 620.11
• DOI: 10.1002/adfm.201702994
• Languages: English
• ISSNs: 1616-301X

Abstract

Abstract: Attempts to rationally tune the macroscopic mechanical performance of supramolecular hydrogel networks through noncovalent molecular interactions have led to a wide variety of supramolecular materials with desirable functions. While the viscoelastic properties are dominated by temporal hierarchy (crosslinking kinetics), direct mechanistic studies on spatiotemporal control of supramolecular hydrogel networks, based on host–guest chemistry, have not yet been established. Here, supramolecular hydrogel networks assembled from highly branched cucurbit[8]uril‐threaded polyrotaxanes (HBP‐CB[8]) and naphthyl‐functionalized hydroxyethyl cellulose (HECNp) are reported, exploiting the CB[8] host–guest complexation. Mechanically locking CB[8] host molecules onto a highly branched hydrophilic polymer backbone, through selective binary complexation with viologen derivatives, dramatically increases the solubility of CB[8]. Additionally, the branched architecture enables tuning of material dynamics of the supramolecular hydrogel networks via both topological (spatial hierarchy) and kinetic (temporal hierarchy) control. Relationship between macroscopic properties (time‐ and temperature‐dependent rheological properties, thermal stability, and reversibility), spatiotemporal hierarchy, and chain dynamics of the highly branched polyrotaxane hydrogel networks is investigated in detail. Such kind of tuning of material mechanics through spatiotemporal hierarchy improves our understanding of the challenging relationship between design of supramolecular polymeric materials and their complex viscoelasticity, and also highlights a facile strategy to engineer dynamic supramolecular materials. Abstract : Formation of hydrogel networks through a two‐component strategy from highly branched CB[8]‐threaded polyrotaxanes, exploiting the dynamic CB[8]‐based heteroternary host–guest complexation. The branched architecture enables tuning of the hydrogel network dynamics via both topological (spatial hierarchy) and kinetic (temporal hierarchy) control.