Development of Zn²⁺ Mediated Hydrogel With Reversible and Dynamic Crosslinking Network

ABSTRACT Metal ion‐assisted hydrogels are of growing interest because of their excellent mechanical properties, fast recovery, and self‐healing ability. However, affording all these properties in a single polymeric framework is very challenging. This paper presents a facile one‐pot synthesis of Zn 2+ coordinated hydrogels by using acrylic acid and acrylamide monomer as precursors. Special emphasis has been placed on the types of zinc salt that have not been studied before. Zinc coordination provides the hydrogel with prominent mechanical strength, toughness, stretchability, and self‐healing properties without any stimulation, due to the numerous entanglements of polymeric chains. Rheology studies demonstrate that various zinc salts used for coordination with polymeric functional groups could influence the mechanical properties of the gels to different extents. The highest self‐healing potential is exhibited by MGel‐ZnCl 2 (up to 90% recovery) while those for MGel, MGel‐Zn(NO 3 ) 2 , and MGel‐ZnSO 4 are 60%, 62%, and 64%, respectively. Dynamic mechanical analysis reveals higher compressive strength (0.86 MPa) of MGel‐ZnSO 4 when compared to other samples viz. MGel (0.48 MPa), MGel‐Zn(NO 3 ) 2 (0.49 MPa), and MGel‐ZnCl 2 (0.45). On the other hand, MGel‐Zn(NO 3 ) 2 offers remarkable compressive strain stability at ε % = 66.63 surpassing those of MGel ( ε % = 11.05), MGel‐ZnCl 2 ( ε % = 55), and MGel‐ZnSO 4 ( ε % = 17).