Universal dynamical onset in water at distinct material interfaces

Interfacial water remains liquid and mobile much below 0 degrees C, imparting flexibility to the encapsulated materials to ensure their diverse functions at subzero temperatures. However, a united picture that can describe the dynamical differences of interfacial water on different materials and its role in imparting system-specific flexibility to distinct materials is lacking. By combining neutron spectroscopy and isotope labeling, we explored the dynamics of water and the underlying substrates independently below 0 degrees C across a broad range of materials. Surprisingly, while the function-related anharmonic dynamical onset in the materials exhibits diverse activation temperatures, the surface water presents a universal onset at a common temperature. Further analysis of the neutron experiment and simulation results revealed that the universal onset of water results from an intrinsic surface-independent relaxation: switching of hydrogen bonds between neighboring water molecules with a common energy barrier of similar to 35 kJ mol(-1).

Automated summary

This study reveals that the onset temperature of surface water is universal, despite the diverse activation temperatures of function-related anharmonic dynamics in different materials. This universal onset results from the switching of hydrogen bonds between neighboring water molecules with a common energy barrier of approximately 35 kJ mol(-1).