Theory of freezing point depression and materials damage by nano-fluidic salt trapping*

The electrolyte solution inside the pore space of many functional materials are subjected to freeze-thaw cycles in a cold season, often undermining the material structure and eventually leading to failure. For more durable designs, it is crucial to understand the interplay between pore surface charge, salt ions and pore connectivity during freezing. We present a continuum theory to distinguish nano-fluidic confined freezing from open systems, and calculate freezing point depression, supercooling and pressure in both limits. As an example application, we provide a possible explaination for the mechanism of freeze-thaw damage in cement paste. Our findings could also provide some insights for cryopreservation and survival of species in winter.