Preparation Of Polyacrylic Polymer Self-Healing Hydrogel With Enhanced Mechanical Performance Via Metal Ions Coordination

Human skin,muscles,and ligaments exhibit self-repairing properties based on capsule,vascular,and intrinsic system effects.Inspired by biological systems in which damage triggers an autonomic healing response,self-healing materials can repair damage when cracked,which prolong their lifetime and save cost.Self-healing materials attracting more attention and can be used in various fields including medical,heavy ions detection,catalyze,supercapacitor,drug delivery,etc.Among self-healing materials,self-healing hydrogel exhibits as a promising candidate in the biomedical field for drug delivery and tissue engineering.Metal coordination bonds give some characteristic properties to the hydrogel,such as dynamic exchangeability,intrinsic self-healing and the ability to recover from deformation.In order to develop hydrogels with advanced capabilities,polyvalent metal ions cross-links can be exploited to achieve more dynamic non-covalent interactions.For self-healing ability,dynamic molecular bonds are often introduced in the hydrogel networks to restore the original mechanical properties.Metal coordination is the most widely used in the fabrication of self-healing hydrogels among all the dynamic molecular bonding interactions.In this paper,we studied the non-covalent bonds interaction among a natural polymer chitosan?CS?and synthetic polymer polyacrylamide?PAM?and polyacrylic acid?PAA?and fabricated a new type of hydrogels(CS/PAA-Fe³⁺and PAM/PAA-Tb³⁺hydrogels)with high toughness and self-healing properties.Introducing the Fe³⁺ions into the hydrogen-bonded CS/PAA double network gives the CS/PAA-Fe³⁺hydrogel with excellent mechanical properties and self-healing ability.The hydrogel exhibits high tensile strength?0.25 MPa?and longer strain at breakpoint?1350%?,high toughness(0.63 MJm^-3)and excellent self-healing efficiency?93%?.By changing the types of metal ions and macromolecules,PAM/PAA-Tb³⁺hydrogels with both luminescent properties and self-healing properties were prepared by introducing Tb³⁺into the PAM/PAA network.The hydrogel also had good mechanical properties and self-healing ability.Tensile,compression and rheological tests were performed to measure their mechanical strength during this study.