Ice nucleation on hydrophilic silicon.
We have used Fourier transform infrared spectroscopy to study thin water films on a hydrophilic silicon surface in the temperature range from 20 to -20 degrees C. Throughout that range, the spectra of the water adjacent to the silicon surface are consistent with that of bulk water near 25 degrees C. Thicker films (>1 microm) freeze at -11+/-1 degrees C. We reconcile the apparent paradox of a thin film of water which is quite liquidlike at a temperature where freezing of thicker films occurs by hypothesizing that the nucleation event in the thicker film is triggered by a critical ice embryo which forms at some small distance from the silicon surface, as opposed to in direct contact with it.
Ochshorn
Eli
E
Department of Physics, Michigan Technological University, 1400 Townsend Dr., Houghton, Michigan 49931, USA. ekochsho@mtu.edu
Cantrell
Will
W