Topology as a limiting factor for mechanical properties in disordered networks

Disordered networks are ubiquitous in both natural and synthetic systems, with mechanical properties that span from significantly compliant to extremely rigid. While the significance of network topology in determining their overall mechanical properties has been established, the coupling between network topology and intrinsic material properties to control elasticity and fracture is not well understood. Here, we show that although the topology of two-dimensional disordered networks defines the occurrence of local network bond rupture events, it is the material properties of the constituent material that dictate the energy required to cause failure. Our results reveal opposite trends between the stiffness and fracture properties that depend on the constituent material, which is linked to how topology and materials couple to enhance either the local stiffness or extensibility of the network. We apply this understanding to transform the mechanical properties of an intrinsically low-toughness material to a tough one on demand.