Large deformation study of temperature-sensitive hydrogel

When the elastomer submerged in aqueous solution, temperature-sensitive hydrogels undergo a phase transition at a particular temperature, i.e. the volume of hydrogels changes with temperature discontinuously. In this paper, the inhomogeneous large deformation of temperature-sensitive hydrogels has been studied. Based on the monophasic gel inhomogeneous field theory, the governing equations and conditions of equilibrium for temperature-sensitive hydrogel have been derived. Furthermore, the free-energy function and derived constitutive equations for temperature-sensitive hydrogel are implemented using Finite Element Method. As an example, a uniaxially constrained-swelling hydrogels with cubic initial shape is studied. The simulating results are in reasonable agreement with available experimental data and analytical solutions. By analyzing the factors affecting the phase transition temperature of hydrogel, we suggest one possible chemical mechanism for the swelling behavior of temperature-sensitive gel during the phase transition process. Also we demonstrate the application of the proposed approach in the analysis of the complex phenomenon, such as to explain the deformation of implant in skin reconstruction. We hope this approach can explain various complex phenomena and provide a useful tool for further theoretical and experimental studies.