Freezing, drying, and/or vitrification of membrane-solute-water systems

Membranes are often damaged by freezing and/or dehydration, and this damage may be reduced by solutes. In many cases, these phenomena can be explained by the physical behavior of membranes-solute-water systems. Both solutes a nd membranes reduce the freezing temperature of water, although their effec ts are not simply additive. The dehydration of membranes induces large mech anical stresses in the membranes. These stresses produce a range of physica l deformations and changes in the phase behavior. These membrane stresses a nd strains are in general reduced by osmotic effects and possibly other eff ects of solutes-provided of course that the solutes can approach the membra ne in question. Membrane stresses may also be affected by vitrification whe re this occurs between membranes. Many of the differences among the effects of different solutes can be explained by the differences in the crystalliz ation, vitrification, volumetric, partitioning, and permeability properties of the solutes. (C) 1999 Academic Press.