Determination of material parameters for a multiphasic modeling of hydrogels.

Stimuli‐responsive hydrogels are electroactive polymers classified as smart materials, consisting of a solid, fluid and ionic phase. As a result of external stimuli, for example through a variation of the chemical conditions in the surrounding solvent, the hydrogels undergo a reversible volume transformation caused by the absorption or the release of solvent. By using a multiphasic model based on the Theory of Porous Media the chemo‐electro‐mechanical interaction of the different phases can be described. Therefore this model requires a large amount of material parameters, whose determination poses a challenge. To determine the parameters for the mechanical behavior it should be ensured that an interaction of the different phases (solid and fluid) and the surrounding solution bath is realized in order to investigate the viscoelastic behavior of the hydrogel. In the present research, a tensile test is performed to identify the mechanical properties of such stimuli‐responsive hydrogels. Therefore, a specific focus is placed on the dependence of these properties on the solid‐fluid ratio due to the multiphasic composition of this material. The aim of this research is to ameliorate the material equations of the modeling and consequently enhance a prediction of the mechanical behavior. [ABSTRACT FROM AUTHOR]