Designing nanoparticles as glues for hydrogels: insights from a microscopic model

We use coarse-grained modeling and (non-equilibrium) molecular dynamics simulations to study how the interface adhesion between two hydrogels can be strengthened by the presence of nanoparticles. Solution of nanoparticles can be used as a general platform to design glues for polymer-based gels. However, optimisation of the system for a specific gel type requires understanding how different experimentally tuneable parameters concur to determine the gel-gel interfacial adhesion. More precisely, here we study the effect of nanoparticle size and affinity for the polymer network and show how the interplay between different physical mechanisms lead to a non-monotonic reinforcement behaviour. Our results also suggest an important role of the nanoparticle size distribution, and of the associated polydispersity. What we show is of particular importance when considering this system for technological applications such as the development of nanoparticles-based glues for biogels, a general platform recently introduced by the Leibler group for the development of suture-less wound healing [Rose et al, Nature 505, 382 (2014)]