Energy Dissipation and Stress Redistribution in Composite Gels

Multi-component gels can be designed to display extraordinary materials properties. In particular, it has been shown that combining networks featuring opposite and complementary mechanical properties yields a composite material of ultrahigh toughness. Experimental studies have argued that these emergent characteristics are signatures of the ability of composite gels to dissipate energy and redistribute stresses. While in these experiments the focus is often on the materials properties of the individual components being mixed, we recently argued that composite properties could be harbingers of the interactions between the two components. Indeed, we showed that by tuning the inter-species interactions alone it is possible to obtain several gel architectures featuring different rheological properties and distinct robustness to changes in the parameters of inter-species interactions. We discuss these different classes of gels, and we show that they display diverse dissipative capacities and peculiar propensities to redistribute stresses throughout the network. We formulate predictions that can be tested in experiments by combining rheology and confocal microscopy.