Agar/PAAc-Fe3+ hydrogels with pH-sensitivity and high toughness using dual physical cross-linking

As promising structural materials, various tough hydrogels have been developed recently by incorporating various kinds of bonds. An important challenge is to use dual physical cross-linking to develop both toughness and self-recovery in a single material. Here we report smart, strain-responsive hydr...

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Bibliographic Details
Published in:Iranian polymer journal 2018-11, Vol.27 (11), p.829-840
Main Authors: Li, Xuefeng, Zhang, Yikun, Yang, Qian, Li, Dapeng, Zhang, Gaowen, Long, Shijun
Format: Article
Language:English
Subjects:
Acrylic acid
Ceramics
Chemistry
Chemistry and Materials Science
Composites
Crosslinking
Ferric ions
Flexible components
Glass
Hydrogels
Hydrogen bonding
Materials recovery
Natural Materials
Original Research
Polymer Sciences
Sensitivity
Tissue engineering
Toughness
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Summary:As promising structural materials, various tough hydrogels have been developed recently by incorporating various kinds of bonds. An important challenge is to use dual physical cross-linking to develop both toughness and self-recovery in a single material. Here we report smart, strain-responsive hydrogels composed of a fully physically linked agarose/poly(acrylic acid)-ferric ion (agar/PAAc-Fe 3+ ) double network (DN) with high toughness and pH-sensitivity. These hydrogels were fabricated in a one-pot reaction to generate dual physical cross-linking through, first, a hydrogen-bonded cross-linked agarose network, and, second, a physically linked PAAc-Fe 3+ network via Fe 3+ coordination interactions. The DN hydrogels possessed high toughness, with breaking strain of 1130%, fast self-recovery properties in ambient conditions (100% recovery in 30 min) and self-healing properties (the healed hydrogels can be manually stretched up to 700% of their original length after self-healing for 60 h from the cut-off state). In addition, the hydrogels exhibited pH-sensitivity due to the dissociation of ionic coordinate bonds between –COO − ions of the PAAc chains and Fe 3+ ions. Double-layer hydrogel strips with two different concentrations of PAAc formed a “C”-shaped material when initially immersed in pH 7 solution and then soaked in a pH 3 solution. These characteristics make the hydrogels attractive candidates for tissue engineering, soft actuators and flexible electronics.
ISSN:1026-1265
1735-5265
DOI:10.1007/s13726-018-0657-y