Microscopic picture of cooperative processes in restructuring gel networks
Jader Colombo, Asaph Widmer-Cooper, and Emanuela Del Gado
Accepted
Colloidal gel networks are disordered elastic solids that can form even in extremely dilute particle suspensions. With interaction strengths comparable to the thermal energy, their stress-bearing network can locally {\it restructure} via breaking and reforming interparticle bonds. This allows for yielding, self-healing and adaptive mechanics under deformation. Designing such features requires controlling stress-transmission through the complex structure of the gel and this is challenging because the link between local restructuring and overall response of the network is still missing. Here, we use a space resolved analysis of dynamical processes and numerical simulations of a model gel to gain insight into this link. We show that consequences of local bond-breaking propagate along the gel network over distances larger than the average mesh size. This provides the missing microscopic explanation for why non-local constitutive relations are necessary to rationalize the non-trivial mechanical response of colloidal gels.