Poly(acrylic acid)-chitosan @ tannic acid double-network self-healing hydrogel based on ionic coordination

In this work, poly(acrylic) acid-chitosan @ tannic acid-aluminum ion (PAA-CS@TA-Al3+) double-network hydrogel was prepared via prefabrication, blending method, and Al3+ immersion method. The interaction between chitosan and tannic acid (CS@TA) was analyzed using Fourier transfer infrared spectra and UV-Vis spectra. The UV-Vis spectrum was also used to confirm the formation of ionic coordination in the gel. Then, the possible coordination modes were studied and analyzed. The microscopic pore structure and macroscopic strain behavior of the gel were analyzed using SEM and tensile testing, respectively, which verified that the tensile strength (approximate to 32 KPa) and elongation at break (approximate to 1700%) of the gel primarily resulted from its crosslinking structure. In addition, the gel also demonstrated a good self-healing performance with recovery approximate to 92.2% at 60 minutes. Hence, the proposed novel self-healing gel can provide inspiration for the preparation of future self-healing gels.