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Dual‐Crosslink Physical Hydrogels with High Toughness Based on Synergistic Hydrogen Bonding and Hydrophobic Interactions
Author(s) -
Chang Xiaohua,
Geng Yuhui,
Cao Heqing,
Zhou Jian,
Tian Ye,
Shan Guorong,
Bao Yongzhong,
Wu Zi Liang,
Pan Pengju
Publication year - 2018
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.201700806
Subject(s) - self healing hydrogels , hydrogen bond , alkyl , materials science , hydrophobic effect , methacrylate , polymer chemistry , supramolecular chemistry , non covalent interactions , toughness , chemical engineering , acrylate , ultimate tensile strength , polymer , polymerization , chemistry , organic chemistry , molecule , composite material , monomer , engineering
Constructing dual or multiple noncovalent crosslinks is highly effective to improve the mechanical and stimuli‐responsive properties of supramolecular physical hydrogels, due to the synergistic effects of different noncovalent bonds. Herein, a series of tough physical hydrogels are prepared by solution casting and subsequently swelling the films of poly(ureidopyrimidone methacrylate‐ co ‐stearyl acrylate‐ co ‐acrylic acid). The hydrophobic interactions between crystallizable alkyl chains and the quadruple hydrogen bonds between ureidopyrimidone (UPy) motifs serve as the dual crosslinks of hydrogels. Synergistic effects between the hydrophobic interactions and hydrogen bonds render the hydrogels excellent mechanical properties, with tensile breaking stress up to 4.6 MPa and breaking strain up to 680%. The UPy motifs promote the crystallization of alkyl chains and the hydrophobic alkyl chains also stabilize UPy–UPy hydrogen bonding. The resultant hydrogels are responsive to multiple external stimuli, such as temperature, pH, and ion; therefore, they show the thermal‐induced dual and metal ion‐induced triple shape memory behaviors.