Young's Modulus of Two-Dimensional Ice from the Electrostatic Compression of Mercury/Water/Mercury Tunnel Junctions

Solid-water films thinner than 0.8 nm were confined between the mercury surfaces of a squeezable tunnel junction at 265 ± 3 K. Uniaxial compression of the films was performed electrostatically by changing the junction bias. Mean compressive displacements were calculated from the nonlinear current response of the junction. Young's moduli of stable ice bilayers were estimated to be 134 MPa ± 18% (stat) ± 70% (sys), or about 1%-2% of the value of bulk ice ${\mathrm{I}}_h$. Moduli of ice "double bilayers" decreased with increasing film thickness, from a maximum of ∼20% of the bulk value.