Microstructure and Mechanical Properties of Jammed Dispersion of Nanogels

High Resolution Image Download MS PowerPoint Slide This study employs dissipative particle dynamics simulations to investigate the equilibrium microstructure and mechanical properties of jammed nanogel dispersions in a good solvent. The nanogels, composed of cross-linked linear polymers, exhibit impenetrability. Significant changes in size (radius of gyration) and shape (asphericity parameter) occur beyond a critical concentration (e.g., 15 wt %), resulting in densely packed configurations. The coordination number increases with rising concentration and stabilizes at a constant (approximately 13) for a jammed structure. For the jammed dispersion (25 wt %), rheological measurements reveal shear-thinning behavior and the presence of a static yield stress. Furthermore, oscillatory tests confirm the dominance of the storage modulus, indicating solid-like behavior. According to the compressive test, the Young’s modulus increases with the nanogel concentration due to denser packing. Free relaxation tests show an elastic response for small strains but a plastic response for large strains. This comprehensive analysis elucidates the relationship between the microstructure of nanogel dispersions and their solid-like characteristics.