Rate-Dependent Stiffness and Recovery in Interpenetrating Network Hydrogels through Sacrificial Metal Coordination Bonds

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• 作者：Matthew S. Menyo ; Craig J. Hawker ; J. Herbert Waite
• 刊名：ACS Macro Letters
• 出版年：2015
• 出版时间：November 17, 2015
• 年：2015
• 卷：4
• 期：11
• 页码：1200-1204
• 全文大小：334K
• ISSN：2161-1653

文摘

Four-arm poly(ethylene glycol) (PEG) star polymers modified with 3-hydroxy-4-pyridinone (HOPO) end groups were shown to form transient, coordination networks upon addition of trivalent cations In³⁺, Fe³⁺, and Al³⁺. These coordination-based hydrogels exhibited high activation energies of viscoelasticity (34 kT) and characteristic bond lifetimes tunable over 2 orders of magnitude and could be incorporated into poly(hydroxyethylacrylamide)-based covalent scaffolds to create interpenetrating network hydrogels. Measurements carried out in compression and tension demonstrate that the secondary coordination network imparts toughness and stiffness to the overall material, and unlike traditional interpenetrating networks (IPNs), the extent of toughening is dependent on the rate at which the materials are deformed. The dynamic character of the coordination network also allows recovery after mechanical damage following high amplitude strains.