Synthesis, characterization and application of oligomeric proanthocyanidin-rich dual network hydrogels

A structurally dense hydrogel, with strong hydrogen bonding networks, was formed from poly(vinyl alcohol), sodium alginate, and oligomeric proanthocyanidins, using a combination of freeze–thaw cycles and calcium ion cross-linking. The structure of the hydrogel was characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. Mechanical testing and thermogravimetric analysis showed that incorporation of proanthocyanidins enhanced both the mechanical properties and the thermal stability of the hydrogel. The hydrogel was also demonstrated to have excellent ultraviolet resistance and antioxidant properties. The hydrogel was further shown that this hydrogel is also capable of generating electrochemical reactions, which strongly suggests that this hydrogel has exciting potential in many fields.