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Strong Tough Polyampholyte Hydrogels via the Synergistic Effect of Ionic and Metal–Ligand Bonds
Author(s) -
Huang Yiwan,
Xiao Longya,
Zhou Ju,
Liu Tao,
Yan Yongqi,
Long Shijun,
Li Xuefeng
Publication year - 2021
Publication title -
advanced functional materials
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.069
H-Index - 322
eISSN - 1616-3028
pISSN - 1616-301X
DOI - 10.1002/adfm.202103917
Subject(s) - self healing hydrogels , ionic bonding , materials science , ligand (biochemistry) , metal ions in aqueous solution , metal , chemical engineering , electrolyte , nanotechnology , ion , chemical physics , polymer chemistry , chemistry , organic chemistry , electrode , biochemistry , receptor , metallurgy , engineering
Despite existing in biological systems, developing synthetic polyampholyte (PA) hydrogels constructed by both ionic and metal–ligand bonds remains challenging. Herein, a simple secondary equilibrium approach is proposed to fabricate strong and tough PA hydrogels via the synergy of ionic and metal–ligand bonds. The original PA gels (constructed by ionic bonds) are first dialyzed in multivalent metal‐ion solutions to reach a swelling equilibrium and then moved to deionized water to dialyze excess free ions to achieve a new equilibrium. Through this approach, the original PA gel network can be optimized and eventually constructed by ionic and metal–ligand bonds, enabling a synergistic reinforcement. By selecting different original PA gel systems and diverse multivalent metal‐ions, the proposed approach is proved to be generalizable to fabricate strong and tough PA gels. Additionally, the hydrogels have stable ion‐conductivity even at the water‐equilibrium state, making them promising as strain sensors. The viscoelastic and elastic contributions to the mechanical properties of the hydrogels by a viscoelastic model are also discussed to further understand the strengthening and toughening mechanisms. The proposed strategy is simple but effective for achieving strong and tough PA‐based hydrogels. This study also provides new insights for PA hydrogels in electrolyte environments.