COEXISTENCE OF SOLID AND SUPERCOOLED LIQUID. THERMODYNAMIC EQUILIBRIUM AND DYNAMICS

Abstract

We study the thermodynamic equilibrium between supercooled liquid and solid using a homemade MEMS device called microtensiometer to directly measure the pressure and temperature of a macroscopic volume of supercooled liquid in equilibrium with solid. Our measurements on water are consistent with the generalized Clapeyron equation, which predict the relation between the pressure of the liquid, the pressure of the solid and the temperature at equilibrium. We also report and discuss remarkable behaviors in the kinetics of equilibration. We found that the equilibration time to reach chemical equilibrium can vary by several orders of magnitude. To better understand this observation, we do a more careful study of the dynamics of transport of supercooled water into ice using a custom-made microfluidic platform. Our results indicate that the dynamics is slower than the prediction of the generalized Clapeyron equation, assuming that the ice remains at atmospheric pressure. We speculate that the transport impacts the pressure in the ice and leads to an effectively lower driving force.