Rheological Behavior of Polymer-Grafted Silica Nanomaterials Embedded in Ice Matrices

Polymer-grafted silica nanomaterials exhibit unique interfacial properties that influence freezing and mechanical behavior of surrounding water and ice. These nanomaterials combine rigidity and high surface area of silica with the tunable chemistry of the polymer chains, enabling controlled interfacial interactions and mobility in aqueous environments. This study investigates how polymer chain length and grafting density affect ice formation, and the subsequent rheological response of the frozen system. Using coarse-grained molecular dynamics simulations, the freezing process is analyzed by monitoring water structure evolution and ice growth near polymer-grafted nanoparticles (PGNPs) and polymer-grafted surfaces (PGSs). After solidification, shear simulations are performed to evaluate the viscoelastic and frictional behavior of the whole system. Key rheological parameters such as sliding coefficient, stress-strain response, and frictional behavior are calculated to understand the mechanisms governing interfacial sliding and energy dissipation. The results show both polymer grafting density and chain flexibility play critical roles in determining interfacial adhesion and mobility at the ice-polymer interface. Comparisons between PGNP and PGS systems highlight distinct deformation and frictional characteristics offering molecular-level insights for tuning polymer-grafted interfaces to control ice mechanics and tribological performance under freezing conditions.