A model for thermal hysteresis utilizing the anisotropic interfacial energy of ice crystals

The mechanism of action of fish antifreeze agents is often modeled by an adsorption-inhibition process utilizing the Gibbs-Thomson or Kelvin effect of interface curvature. To date there is no direct evidence for the increase in interface curvature required by this model. In this paper we introduce a new model for thermal hysteresis which utilizes the anisotropic interfacial energy of polygonal ice crystals. While the maximum hysteresis found in polar fishes is 1.5°C, some cold-hardy insects have more than 6°C of hysteresis. The new model explains this difference in terms of the higher osmolality of the insect hemolymph causing an increase in the absolute anisotropy of the surface free energies of particular ice crystal faces.