Significance Fracture in soft materials often couples a wide range of time and length scales. To date, research is mostly focused at the meso- and macroscale in which the continuum mechanics approach is expected to work, and the deformation surrounding the crack tip can be directly observed. Yet understanding at the network scale is very limited. A relevant question is how does chain dynamics at the network scale control fracture in rate-independent materials? Here, we study the role of polymer dynamics on the fracture and nonlinear crack tip behaviors of rate-independent double-network gels. We believe this work is crucially important for understanding the dynamic molecular process of fracture and for further facilitating theoretical approaches to predict failure in soft materials.