Identification of the viscoelastic properties of a hydrogel in sol-gel transition by vibration experiments

Soft viscoelastic materials, such as hydrogels, are widely used by biomedical and agri-food industries. The characterization of their transition from solution (liquid) to gel (solid) state is often necessary for manufacturing processes and quality control. This study aims at character-izing the viscoelastic properties of a hydrogel in sol-gel transition by measuring the vibration response of the bottom silicone membrane of a rigid circular cylindrical container subjected to base excitation. The static deflection of the membrane for increasing sample filling height was measured. The frequency-responses of the membrane alone and of the membrane coupled to a hydrogel during sol-gel transition were measured for increasing filling heights. A finite-element numerical model was built for the identification of the storage shear modulus and loss tangent of the hydrogel. Both a slip and a no-slip conditions of the hydrogel at the inner wall of the container were applied and their effects were compared. The static deflection was calculated and compared to the experiments. The parameters of a dynamic model of the coupled membrane- hydrogel were identified. The evolution of the identified material parameters enables to follow the sol-gel transition of the hydrogel. Results show that the membrane vibration can be used to characterize the viscoelastic mechanical properties of a hydrogel in sol-gel transition through a more versatile approach.

Automated summary

This study characterizes the viscoelastic properties of a hydrogel in sol-gel transition by measuring the vibration response of a rigid circular cylindrical container's bottom silicone membrane. A finite-element numerical model was built for identification of the hydrogel's storage shear modulus and loss tangent. It was found that membrane vibration can be used to characterize the viscoelastic mechanical properties of a hydrogel in sol-gel transition in a more versatile way.