One-pot fabrication of triple-network structure hydrogels with high-strength and self-healing properties

We recently proposed and demonstrated a novel strategy to improve mechanical strength by designing triple-network (TN) structure. The hydrogel composed of polyacrylamide (PAM), gelatin (Gela) and polyvinyl alcohol (PVA) was prepared by a simple one-pot method of copolymerization, cooling and freezing/thawing. The PAM/Gela/PVA hydrogels with 2% Gela and 8% PVA could achieve high mechanical properties, the strain and stress at break were 256% and 500 kPa, respectively, and the compression strength could reach 4.6 MPa under the deformation of 85% which exhibited superior mechanical properties than those of single network (SN) and double network (DN) hydrogels. What's more, the hydrogels exhibited self-healing property. Thus, the TN concept should be applicable to developing tough hydrogels which provided insight into how these polymers played a role as structural components in cartilage and other tissues.