Konjac glucomannan/kappa carrageenan interpenetrating network hydrogels with enhanced mechanical strength and excellent self-healing capability

Abstract

Konjac glucomannan (KGM) hydrogels have attracted considerable interest in many fields, such as drug delivery, tissue engineering, bio-medicine, and food processing, due to their good biocompatibility, biodegradability, gelation performance and security. However, KGM hydrogels prepared by traditional methods often exhibit poor mechanical properties, severely limiting their practical applications. To obtain hydrogels of excellent mechanical performance, a simple one-step method was developed. Through this method, KGM/kappa-carrageenan (KC) hydrogels of interpenetrating network (IPN) structure were prepared, where the chemical gel network was constructed via reaction between the KGM and borax and the physical network was built by introducing a KC component. Besides, the –OSO3− groups on the KC chains will also interact with the hydroxyl groups on the KGM chains to form hydrogen bonds, effectively binding the two networks into a whole. We find that the tensile strength of the obtained IPN hydrogels can reach to 100.2 kPa. Since the second physical network structure is temperature sensitive and recoverable, the hydrogels obtained by our method are of excellent self-healing performance. Our results showed that the mechanical strength of the self-healed hydrogels can recover by 96.7% after heat treating at 60 °C for 30 min.