Natural and synthetic multi-component gels display emergent properties, which implies that they are more than just the sum of their components. We have developed a new model and computational approach to investigate the effect of changing the strength of the interaction between two species forming a fibrous double network. Simply changing the strength of inter-species lateral association generates two types of gels: one in which the two components demix, and another one in which the two species wrap around each other. We show that demixing gels have structure and rheology that are largely unaffected by the strength of attraction between the components. In contrast, architecture and material properties of intertwined gels strongly depend on inter-species ``stickiness'' and volume exclusion. These results can be used as the basis of a design principle for double networks which are made to emphasize either stability to perturbations or responsiveness to stimuli. Similar ideas could be used to interpret naturally occurring multi-component gels. Based on these results, we have analyzed how the distinct types of double network architectures determine plasticity and toughness.

Rose Tchuenkam Batoum

Georgetown University

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