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Abstract Recent investigations have pointed to physical entanglements that greatly outnumber chemical crosslinks as key sources of energy dissipation and low friction in hydrogel networks. Slide-ring gels are an emerging class of hydrogels described by their mobile crosslinks, which are formed by rings topologically constrained to slide along linear polymer chains within the network. These materials have enjoyed decades of study by polymer chemists but have been underexplored by the tribology community. In this work, we synthesized a pseudo-rotaxane crosslinker from poly(ethylene glycol) diacrylate (PEG-diacrylate) andα-cyclodextrin-acrylate followed by hydrogel networks by connecting the sliding crosslinks with polyacrylamide chains. The mechanical and tribological properties of slide-ring hydrogels were investigated using a custom-built microtribometer. Slide-ring hydrogels exhibit unique behavior compared to conventional covalently crosslinked polyacrylamide hydrogels and offer a vast design space for future investigations. Graphical Abstract
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This content will become publicly available on May 5, 2027
Synergistic Dual Slip‐Link Toughening of a Water‐Rich Double Network Hydrogel Combining Slide‐Ring and Highly Entangled Networks
ABSTRACT Slide‐ring network (SRN) hydrogels derived from ring‐crosslinked polyrotaxanes exhibit exceptional mechanical properties attributable to a pulley effect, whereby mobile‐ring crosslinks redistribute tension under deformation through a slip‐link mechanism. However, SRN hydrogels weaken severely upon swelling in water, limiting their utility at high water content (90 wt.%). Here, two distinct physical slip‐link mechanisms are combined in a highly entangled slide‐ring double network (HESRDN) hydrogel: the pulley effect of a polyrotaxane slide‐ring network and the entangled chains of a sparsely cross‐linked polyacrylamide network. HESRDN is prepared by photopolymerization of acrylamide/N,N'‐methylenebis(acrylamide) within a partially swollen slide‐ring hydrogel. The dual slip‐link architecture synergistically strengthens and toughens the hydrogel far beyond the sum of the component networks, yielding high work of fracture (1275 kJm−3), toughness (2020 Jm−2), and near‐complete reversibility (99.7%) at 91 wt.% water. HESRDN withstands continuous friction for over 12 h without rupture, compared to minutes for the SRN and 5 h for the HEN component networks, reflecting the unique capacity of the dual slip‐link architecture to delocalize and redistribute stress under sustained mechanical loading.
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- Award ID(s):
- 2023179
- PAR ID:
- 10692707
- Publisher / Repository:
- Wiley
- Date Published:
- Journal Name:
- Advanced Science
- ISSN:
- 2198-3844
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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