Synthesis of Double Network Hydrogels Which Can Be Shaped Freely

Double network (DN) hydrogels have specific characters such as flexibility and high mechanical strength. They are expected to use biomaterials such as artificial cartilages and meniscuses. The purpose of this study is to synthesize DN gels which can be shaped freely. DN gels were synthesized by polyvinyl alcohol (PVA) as a mold, 2-acrylamide-2-methylpropane sulfonic acid (AMPS) as a first monomer, N,N’-methylene-bis-acrylamide (MBAA) as a crosslinker, 2-oxoglutalic acid (OGA) as an initiator and acrylamide (AAm) as a second monomer. First, PVA (polymerization degree; 2000) was dissolved in the water and prepared to 15 % of aqueous solution. It was poured in the silicone mold and was kept -28 degrees in the freezer and thawed after that. Second, the PVA gels were immersed in the first monomer solution containing AMPS (1.0 mol/L), MBAA (1.0×10⁻² mol/L) and OGA (5.0×10⁻³ mol/L). They were irradiated with UV rays (360 nm) in a nitrogen atmosphere for 6 hours. Third, the (PVA-PAMPS) gels were immersed in the second monomer solution containing AAm (1.0 mol/L), MBAA (2.5×10⁻³ mol/L) and OGA (5.0×10⁻⁴ mol/L). They were irradiated with UV rays in the same condition. Through these methods, DN gels were obtained by the shape which we aimed at. In the future, we would like to synthesis DN gels which are made by natural materials.