Dual Crosslink Hydrogels with Metal-Ligand Coordination Bonds: Tunable Dynamics and Mechanics Under Large Deformation
Résumé
13 14 Introducing additional physical and reversible crosslinks to a chemically crosslinked 15 hydrogel is an interesting and viable alternative to increase the toughness of a hydrogel. Yet 16 while in general the physical crosslink points provide dissipative mechanisms, there are still 17 many details that are unknown in particular on the role that physical crosslinks play on the 18 large strain behavior. We explore the mechanical properties in small and large strain of two 19 dual crosslink gels made from a random copolymer of Poly(acrylamide-co-vinylimidazole) 20 with a range of elastic moduli in the tens of kPa. The interaction between vinyl imidazole 21 groups and Metal ions (Zn 2+ and Ni 2+) results in physical crosslink points and in a markedly 22 stretch rate dependent mechanical behavior. While a main relaxation process is clearly 23 visible in linear rheology and controls the small and intermediate strain properties, we find 24 that the strain hardening behavior at stretches of > 4 and the stretch at break b are 25
Domaines
Matière Molle [cond-mat.soft]
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