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Hydrogen‐Bonding Toughened Hydrogels and Emerging CO 2 ‐Responsive Shape Memory Effect
Author(s) -
Xu Bing,
Zhang Yinyu,
Liu Wenguang
Publication year - 2015
Publication title -
macromolecular rapid communications
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.348
H-Index - 154
eISSN - 1521-3927
pISSN - 1022-1336
DOI - 10.1002/marc.201500256
Subject(s) - self healing hydrogels , hydrogen bond , monomer , materials science , toughness , copolymer , polyethylene glycol , polymer chemistry , chemical engineering , ultimate tensile strength , hydrogen , polymer , composite material , molecule , chemistry , organic chemistry , engineering
A double hydrogen bonding (DHB) hydrogel is constructed by copolymerization of 2‐vinyl‐4,6‐diamino‐1,3,5‐triazine (hydrophobic hydrogen bonding monomer) and N , N ‐dimethylacrylamide (hydrophilic hydrogen bonding monomer) with polyethylene glycol diacrylates. The DHB hydrogels demonstrate tunable robust mechanical properties by varying the ratio of hydrogen bonding monomer or crosslinker. Importantly, because of synergistic energy dissipating mechanism of strong diaminotriazine (DAT) hydrogen bonding and weak amide hydrogen bonding, the DHB hydrogels exhibit high toughness (up to 2.32 kJ m −2 ), meanwhile maintaining 0.7 MPa tensile strength, 130% elongation at break, and 8.3 MPa compressive strength. Moreover, rehydration can help to recover the mechanical properties of the cyclic loaded–unloaded gels. Attractively, the DHB hydrogels are responsive to CO 2 in water, and demonstrate unprecedented CO 2 ‐triggered shape memory behavior owing to the reversible destruction and reconstruction of DAT hydrogen bonding upon passing and degassing CO 2 without introducing external acid. The CO 2 triggering mechanism may point out a new approach to fabricate shape memory hydrogels.