Strain-Induced Raman Shifts Due to Ice Adhesion

Ice formed on a material creates a strain that is indicative of the adhesive strength between the ice and substrate. Previous determinations of ice adhesion strength, a critical parameter for understanding icing physics, have proven to be both challenging and highly dependent on experiment-specific conditions (surface roughness, icing conditions, water purity, etc.). In this work, we use Raman spectroscopy to contactlessly and non-destructively measure ice-induced strain on silicon and single-layer graphene. To isolate the ice-material interface, we measured the vibrational modes of graphene from 20⁰C to - 30 ⁰C with and without ice. Along with the well-known temperature-dependent Raman shift of graphene, a clear, ~ 3 cm^-1 change in the G-mode (~1590 cm^-1) frequency developed upon ice formation. We found this change in the Raman shift tracked closely to the temperature-dependent density of ice, suggesting that we are optically measuring ice-created strain in graphene. When correlated with mechanical adhesion measurements, our non-destructive optical technique provides a way to measure ice adhesive strength, which can be extended to various materials.