Developing Mesoscale Computational Models to Explore Hydrogel Friction

We develop a mesoscale computational model to investigate friction of polymeric hydrogels. Our model is based on dissipative particle dynamics (DPD). The gel is modeled as a network of randomly connected elastic filaments using the bead-spring approach. The gel is submerged in an explicit DPD solvent. We examine two configurations. In the first case, hydrogel slides over a flat plate, in which case no slip condition is imposed using bounce back procedure to the DPD bead crossing the solid boundary. In the second scenario, two gels move in opposing directions and slide along each other. To probe friction forces we vary the separation between the gel and the wall or between the gels and their relative velocity. We validate the model and apply it to examine friction of gels with different internal structure.