Growth patterns and interfacial kinetic supercooling at ice/water interfaces at which anti-freeze glycoprotein molecules are adsorbed

Ice crystal growth in a supercooled solution containing proteins such as anti-freeze glycoproteins (AFGPs) is inhibited by its adsorption at the ice/water interface. Although these proteins have dramatic consequences for natural biological processes and technological applications, little is known about the dynamic mechanism of ice growth inhibition. One-directional growth experiments were carried out to observe the pattern formation at the ice/water interface growing from an aqueous AFGP solution. Typical zigzag patterns composed of flat prismatic {101¯0} interfaces were observed in the final quasi-stable growth state. By analyzing the zigzag patterns, we were able to directly determine the interfacial kinetic supercooling, δT, at the interfaces of prismatic faces as a function of growth rate. δT linearly increased with increasing growth rate in the range below a critical growth rate, but its dependence showed the reversed relationship above the critical growth rate. This growth rate dependency of δT was qualitatively explained by the interaction between the rejection and incorporation rates of AFGP molecules at the growing interface.