Adv Polym Sci (2020) 285: 295–318
https://doi.org/10.1007/12_2019_56
© Springer Nature Switzerland AG 2020
Published online: 8 April 2020
Tough and Self-Healing Hydrogels
from Polyampholytes
Tao Lin Sun and Kunpeng Cui
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296
2 Synthesis and Optimized Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298
2.1 Charge Ratio . . . .. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . .. . . . . . . . . 299
2.2 Total Ionic Monomer Concentration . . . . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . 300
2.3 Chemical Cross-Linker Density . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
3 Mechanical Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
3.1 Hysteresis, Self-Recovery, and Self-Healing Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
3.2 Time-Dependent of Tensile and Fracture Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305
4 Toughening Mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308
5 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310
5.1 Adhesion . . . . . . . . . .. . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . .. . . . . . . . . 311
5.2 Fiber-Reinforced Soft Composite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313
6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315
Abstract Polyampholyte (PA) hydrogels have attracted great attention as an innovative material having tough, self-healing, and viscoelastic behavior. PA hydrogels
are synthesized using one-step radical polymerization of equal amounts of oppositely charged ionic monomers at a very high monomer concentration. They have
50–70 wt% of water at an equilibrium state, much lower than that of conventional
hydrogels that usually have a high-water content (>80%). They are strongly viscoelastic and have a high toughness (fracture energy of 1,000–4,000 J/m
2 ), a high
T. L. Sun (*)
South China Advanced Institute for Soft Matter Science and Technology, South China
University of Technology, Guangzhou, China
e-mail: suntl@scut.edu.cn
K. Cui
Laboratory of Soft and Wet Matter, Institute for Chemical Reaction Design and Discovery
(WPI-ICReDD), Hokkaido University, Sapporo, Japan
https://doi.org/10.1007/12_2019_56
© Springer Nature Switzerland AG 2020
Published online: 8 April 2020
Tough and Self-Healing Hydrogels
from Polyampholytes
Tao Lin Sun and Kunpeng Cui
Contents
1 Introduction . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 296
2 Synthesis and Optimized Structure . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 298
2.1 Charge Ratio . . . .. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . .. . . . . . . . . . . . . . . .. . . . . . . . . . . . . . .. . . . . . . . . 299
2.2 Total Ionic Monomer Concentration . . . . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . . . . . . . .. . . . . . . 300
2.3 Chemical Cross-Linker Density . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 301
3 Mechanical Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
3.1 Hysteresis, Self-Recovery, and Self-Healing Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 303
3.2 Time-Dependent of Tensile and Fracture Behavior . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 305
4 Toughening Mechanism . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 308
5 Applications . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 310
5.1 Adhesion . . . . . . . . . .. . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . .. . . . . . . . . . . . . . . . . . . .. . . . . . . . . 311
5.2 Fiber-Reinforced Soft Composite . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 313
6 Summary . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 314
References . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 315
Abstract Polyampholyte (PA) hydrogels have attracted great attention as an innovative material having tough, self-healing, and viscoelastic behavior. PA hydrogels
are synthesized using one-step radical polymerization of equal amounts of oppositely charged ionic monomers at a very high monomer concentration. They have
50–70 wt% of water at an equilibrium state, much lower than that of conventional
hydrogels that usually have a high-water content (>80%). They are strongly viscoelastic and have a high toughness (fracture energy of 1,000–4,000 J/m
2 ), a high
T. L. Sun (*)
South China Advanced Institute for Soft Matter Science and Technology, South China
University of Technology, Guangzhou, China
e-mail: suntl@scut.edu.cn
K. Cui
Laboratory of Soft and Wet Matter, Institute for Chemical Reaction Design and Discovery
(WPI-ICReDD), Hokkaido University, Sapporo, Japan