Anomalies of Mechanical Properties in Nanoparticle Hydrogels

Hydrogels incorporating nanoparticles (NPs) possess new properties that can revolutionize areas such as drug delivery, protein crystallography, and self-assembly of photonic crystals. A key requirement for their successful utilization into many target applications is the understanding of how the spatial arrangement of the NPs contributes to the mechanical properties of the hydrogel. Here we investigate how the viscoelasticity of glutathione (GSH) stabilized CdTe semiconductor NP hydrogels is related to the specific bonding configuration between NPs and their stabilizer. By analytically investigating the ratio of configurational transformations from three-point to single-point bonding, we demonstrate how the macro-mechanical properties of NP hydrogels can be influenced by the configurable coordination between molecules. Our findings are confirmed by Monte Carlo simulations of the formation and mechanical response of hydrogels with different molecular interactions. Our results pave the way for the realization of new multifunctional materials built from the bottom-up.