Nonfreezing water confined in water layer of multilamellar L-α, distearoyl phosphatidylcholine in temperature range between 0 °C and −190 °C

Where multilamellar phospholipid water exists, e.g., inside or outside of the multilamellar phospholipid, depends largely on the percentage of water content. For example, the multilamellar L-α, distearoyl phosphatidylcholine (DSPC) with 44 wt % water content carries water in excess water regions as well as in the water layer inside of the multilamellar DSPC. This excess water freezes at about −20 °C in forms ranging from super-cooled water to homogeneous ice with a hexagonal symmetry. On the other hand, when no excess water exists, e.g., in cases of multilamellar DSPC containing 15 wt % or 11 wt % water, water is contained entirely in the water layer inside of the multilamellar DSPC. When multilamellar DSPC contains 15 wt % water, the state of super-cooled water in the water layer is maintained at about −45 °C and then changes into heterogeneous ice or into many ice nuclei with a hexagonal symmetry in the temperature region of less than −45 °C. In the case of multilamellar DSPC with 11 wt % water content, however, the state of super-cooled water in the water layer remains unchanged even down to −190 °C. X-ray diffraction results prove that the super-cooled water in the water layer of multilamellar DSPC containing 11 wt % water does not freeze even down to −190 °C.