Oral: Ice Formation in the presence of Hydrogels

Antifreeze proteins (AFPs) are macromolecules that can bind to ice crystals and suppress their growth, resulting in freezing point depression and ice recrystallization inhibition (IRI). In recent years, AFPs have been used to mitigate freeze-thaw damage in concrete, resulting in longevity of cementitious infrastructure. Some recent studies indicate that hydrogels can also inhibit the formation of ice in water and little is known about the mechanism of ice binding and subsequent ice growth inhibition in these systems. Thus, we use coarse-grained molecular dynamics (MD) simulations to investigate the effects of polymer-water interactions and polymer crosslinking density on the freezing behavior of confined water. We simulate a defect-free, cubic polymer lattice with fully-flexible polymer chains connecting each permanent crosslink. Water is explicitly included as LJ spheres following the mW model. Our results indicate that freezing point depression highly depends on polymer hydrophobicity or hydrophilicity, whereas a high crosslinking density inhibits ice growth. Such a computational framework can accurately predict ice behavior for a range of polymer architectures, thus enabling geotechnical applications in sub-zero regions.