Preparation and performance of PVA/PAA/Fe3+ supramolecular hydrogels.

In order to improve the mechanical properties of hydrogels and expand their applications, PVA/PAA/Fe³⁺ hydro-gels wjth high mechanical propertiesj+were prepared by using biocompatibie polyvinyl alcohol (PVA) and poly-acrylic acid (PAA) as matrix materials, hydrogen bonds and metal-coordination bonds as physical cross-linking points. The experiment was carried out to study the mechanical properties of the hydrogels by adjusting hydrochloric acid concentration, Fe concentration and soaking time. The stability of the hydrogel was investigated by the pH value of the solution. The self-recovery of the hydrogel was evaluated by cyclic loading-unloading experiment. The results show that the formation of hydrogen bonds and coordination bonds is confirmed by FTIR. The hydrogel has the best mechanical strength with breaking stress of 12.69 MPa and toughness of 41.64 MJ/m under the conditions of 0.2 mol/L hydrochloric acid, 0.09 mol/L Fe and 20 h soaking time. The hydrogel is stable when the pH of solution is 1-9. After a cyclic loading-unloading experiment and waiting for 240 minutes, the stress and strain recovery rates of hydrogels can reach 90% and 87.8% respectively. [ABSTRACT FROM AUTHOR]