Calcium alginate-cross-linked deacetylated konjac glucomannan-based double network hydrogels: Construction, characterizations and gelation kinetics.

Deacetylated Konjac Glucomannan (DKGM) hydrogels frequently fail to meet commercial standards because of their weak gel strength and low mechanical characteristics. In this regard, we successfully constructed DKGM and calcium alginate (CA) double network hydrogels (DKGM/CA DNs) through the two-step sequential network formation technique for the first time. The microstructure, gel properties and gel kinetics of DKGM/CA DNs were investigated in multiple dimensions. Notably after the introduction of CA gel network into DKGM hydrogels, the system's gel network pores became dense, the water freedom decreased, and the gel strength, hardness, gumminess and other properties were 10-25 times higher than pure DKGM hydrogels. Further gel kinetics analysis showed that the presence of sodium alginate (SA) increased the gelation rate of DKGM during the gelation process, shorten the sol-to-gel time, and reduced the complex modulus of the gel system. In contrast, the presence of DKGM hydrogels would hinder the penetration and diffusion of Ca solution, thus slowing down the crosslinking rate of SA and Ca. In summary, this study provides a new solution for improving the mechanical properties of DKGM hydrogels in a green and efficient manner.