Exploring the liquid-like layer on the ice surface.

Using interfacial force microscopy and a spherical glass probe, we investigate the adhesive and mechanical properties of the so-called liquid-like layer (L-LL) on the surface of ice at various temperatures over the range from -10 to -30 degrees C. We find that the layer thickness closely follows that predicted on thermodynamic grounds, while the adhesive interaction has the behavior of a "frustrated capillary", strongly suggesting that the layer is viscoelastic. This viscoelasticity is directly probed using a lateral-dither technique to obtain information on the layer's viscous response as a function of both temperature and interfacial separation.