Multiamine-induced self-healing poly (Acrylic Acid) hydrogels with shape memory behavior

In this work, a versatile and simple strategy for building self-healing hydrogels with tunable mechanical properties and shape memory behavior is reported. A commercially available small molecule with three amino groups, diethylenetriamine (DETA), is applied to crosslink poly (acrylic acid) (PAAc) chains via ionic bonding, and the complexes of the PAAc chains with DETA form hydrophobic microdomains in the hydrogel network. The cooperation of ionic bonding and hydrophobic interactions drastically improves the mechanical properties, which can be modulated by adjusting the molar ratio of PAAc to DETA. Due to the physical interaction of the crosslinks, the hydrogels can self-heal rapidly in ambient conditions. The thermal responsiveness of the physical microdomain crosslinks endow the hydrogels with shape memory behavior. It is hoped that this novel strategy will provide new opportunities for the design of high-strength hydrogels with variable functionalities for a wide range of applications, such as artificial muscle and skin.