Compression modulus and equilibrium swelling studies of poly(2-hydroxyethyl methacrylate) hydrogels formed at various polymer concentrations

The equilibrium swelling degree and modulus of elasticity of poly(2-hydroxyethyl methacrylate) (PHEMA) hydrogels prepared at various initial monomer concentrations were investigated to understand their characteristic behavior for development as biomaterials. The resulting hydrogels were characterized in terms of the equilibrium swelling and compression stress-strain measurements. The influences of the monomer feed composition on the swelling and the mechanical properties of PHEMA hydrogels were explored. The swelling capacity and network characteristics of the resulting hydrogels were determined through the observation of swelling behavior in water and compression modulus determination both after equilibrium swelling and after their preparation. The equilibrium swelling of PHEMA hydrogels was analyzed by Flory-Rehner theory and the results were combined by the results of elasticity measurements to calculate the molecular characteristics of hydrogels. The mechanical strength of PHEMA hydrogels increased greatly by increasing the gel preparation concentration. The results showed that the gel strength and the mechanical properties of hydrogels can be controlled by changing the polymer concentration and the amount of water used in the gel preparation.